EXHIBIT 4.5

                        FORM OF 6% CONVERTIBLE DEBENTURE


                                    DEBENTURE

     NEITHER THESE  SECURITIES NOR THE SECURITIES  ISSUABLE UPON  CONVERSION
     HEREOF  HAVE BEEN  REGISTERED  WITH THE UNITED  STATES  SECURITIES  AND
     EXCHANGE COMMISSION OR THE SECURITIES  COMMISSION OF ANY STATE OR UNDER
     THE SECURITIES ACT OF 1933 (THE "1933 ACT"), AS AMENDED. THE SECURITIES
     ARE RESTRICTED AND MAY NOT BE OFFERED,  RESOLD,  PLEDGED OR TRANSFERRED
     EXCEPT AS  PERMITTED  UNDER THE 1933 ACT  PURSUANT TO  REGISTRATION  OR
     EXEMPTION OR SAFE HARBOR THEREFROM.

No.      99-                                                   US $ ____________
         -------------

                          LIGHTPATH TECHNOLOGIES, INC.

6% CONVERTIBLE DEBENTURE DUE JULY 31, 2002

     THIS  DEBENTURE is one of a duly  authorized  issue of up to  $1,000,000 in
Debentures of LightPath Technologies, Inc., a corporation organized and existing
under the laws of the State of Delaware  (the  "COMPANY")  designated  as its 6%
Convertible  Debentures.  Such Debentures may be issued in series, each of which
may have a different  maturity  date,  but which  otherwise  have  substantially
similar  terms.  Capitalized  terms not defined  herein  shall have the meanings
ascribed to them in the Securities Purchase Agreement,  dated July ___, 1999, by
and among the  Company  and the Buyers (as that term is  defined  therein)  (the
"SECURITIES PURCHASE AGREEMENT").

     FOR VALUE RECEIVED, the Company promises to pay to  ______________________,
the   registered   holder   hereof  (the   "HOLDER"),   the   principal  sum  of
____________________  and 00/100 Dollars (US  $_______________) on July 31, 2002
(the "MATURITY  DATE") and to pay interest on the principal sum outstanding from
time to time in  arrears  (i) upon  conversion  as  provided  herein,  (ii) upon
redemption as provided  herein or (iii) on the Maturity  Date, at the rate of 6%
per annum  accruing  from July 28,  1999,  the date of initial  issuance of this
Debenture.  Accrual of interest shall commence on the first such business day to
occur after the date hereof and shall  continue to accrue on a daily basis until
payment in full of the principal sum has been made or duly provided for.

     This Debenture is subject to the following additional provisions:

          1. The  Debentures are issuable in  denominations  of Ten Thousand and
00/100 Dollars (US $10,000.00) and integral  multiples  thereof.  The Debentures
are  exchangeable  for an equal  aggregate  principal  amount of  Debentures  of

                                       1

different authorized denominations,  as requested by the Holder surrendering the
same.  No service  charge  will be made for such  registration  or  transfer  or
exchange.

          2. The Company  shall be entitled  to  withhold  from all  payments of
principal  of, and  interest  on,  this  Debenture  any  amounts  required to be
withheld under the applicable provisions of the United States income tax laws or
other applicable laws at the time of such payments, and Holder shall execute and
deliver all required documentation in connection therewith.

          3.   This   Debenture   has  been   issued   subject   to   investment
representations  of the  original  purchaser  hereof and may be  transferred  or
exchanged  only in compliance  with the  Securities Act of 1933, as amended (the
"1933 ACT"),  and other  applicable  state and foreign  securities  laws. In the
event of any proposed transfer of this Debenture, the Company may require, prior
to issuance of a new Debenture in the name of such other person, that it receive
reasonable transfer documentation  including legal opinions that the issuance of
the  Debenture in such other name does not and will not cause a violation of the
1933  Act or any  applicable  state or  foreign  securities  laws.  Prior to due
presentment  for  transfer of this  Debenture,  the Company and any agent of the
Company may treat the person in whose name this Debenture is duly  registered on
the  Company's  Debenture  Register  as the  owner  hereof  for the  purpose  of
receiving payment as herein provided and for all other purposes,  whether or not
this  Debenture is overdue,  and neither the Company nor any such agent shall be
affected by notice to the contrary.

          4. (A) The  Holder  of this  Debenture  is  entitled,  at its  option,
subject to the  following  provisions  of this  Section  4, to convert  all or a
portion of this  Debenture  into shares of Class A Common  Stock of the Company,
$.01 par value per share ("COMMON  STOCK") of the Company at any time (except as
set  forth in this  Section  4(A) or in  Section  4(C)  hereunder)  prior to the
Maturity Date, at a conversion price (the "Conversion  Price") for each share of
Common  Stock equal to 80% of the Market Price of the Common Stock as of (X) the
Closing Date or (Y) the Conversion Date,  whichever is lower (but the Conversion
Price shall in no event be less than $0.56 (the "MINIMUM  CONVERSION  PRICE") or
more than $2.00),  as such amounts may be equitably  adjusted in accordance with
Sections 8, 9 and 10 hereof, if applicable. The minimum principal amount a Buyer
may  convert is the lower of (x) at least US  $10,000  (unless if at the time of
such  election  to convert  the  aggregate  principal  amount of all  Debentures
registered to the Holder is less than US $10,000, then the whole amount thereof)
or (y) the  maximum  amount  which the Holder can then  convert  pursuant to the
terms of Section 4(C) hereof.

             (B) Conversion  shall be  effectuated by  delivery by  facsimile or
other delivery to the Company of the form of conversion  notice  attached hereto
as EXHIBIT A executed by the Holder of the  Debenture  evidencing  such Holder's
intention to convert this Debenture or a specified  portion  hereof  ("NOTICE OF
CONVERSION"),  and accompanied, if required by the Company, by proper assignment
hereof in blank.  Subject to the  provisions  of Section 4(C)  hereof,  interest
accrued or accruing from the date of issuance to the date of  conversion  shall,
at the option of the Company, be paid in cash or Common Stock upon conversion at
the Conversion  Price  applicable to such  conversion.  No fractional  shares of
Common  Stock or scrip  representing  fractions  of  shares  will be  issued  on
conversion,  but the number of shares  issuable  shall be rounded to the nearest
whole share.  The date on which notice of conversion is given shall be deemed to

                                       2

be the date on which  the  Holder  faxes or  otherwise  delivers  the  Notice of
Conversion, duly executed, to the Company (the "CONVERSION DATE"), provided that
the Holder shall deliver to the Company the original  Debentures being converted
within five (5) business days  thereafter.  Facsimile  delivery of the Notice of
Conversion  shall be accepted by the Company at facsimile number (505) 342-1111;
ATTN: PRESIDENT.  Certificates representing Common Stock upon conversion will be
delivered within three (3) business days following the Conversion Date.

         (C)  Notwithstanding  any other provision hereof, of the Warrants or of
any of the other  Transaction  Agreements  (as those  terms are  defined  in the
Securities  Purchase  Agreement),  in no event  (except  (i) with  respect to an
automatic  or  mandatory  conversion,  if any, of a Debenture as provided in the
Debentures,  (ii) as specifically  provided in this Debenture as an exception to
this  provision,  or (iii) while there is  outstanding a tender offer for any or
all of the shares of the Company's Common Stock) shall the Holder be entitled to
convert any Debenture or shall the Company have the  obligation,  to convert all
or any portion of this  Debenture  (and the Company  shall not have the right to
pay interest on this Debenture in the form of Common Stock ) to the extent that,
after  such  conversion,  the sum of (1) the  number of  shares of Common  Stock
beneficially owned by the Holder and its affiliates (other than shares of Common
Stock  which may be deemed  beneficially  owned  through  the  ownership  of the
unconverted  portion of the Debentures or unexercised  portion of the Warrants),
and (2) the number of shares of Common Stock issuable upon the conversion of the
Debentures or exercise of the Warrants  with respect to which the  determination
of this  proviso is being made,  would  result in  beneficial  ownership  by the
Holder and its affiliates of more than 9.99% of the outstanding shares of Common
Stock (after taking into account the shares to be issued to the Holder upon such
conversion  or  exercise).  For  purposes  of the  proviso  to  the  immediately
preceding sentence,  beneficial ownership shall be determined in accordance with
Section  13(d) of the  Securities  Exchange  Act of 1934,  as amended (the "1934
ACT"), except as otherwise provided in clause (1) of such sentence.  The Holder,
by its acceptance of this Debenture, further agrees that if the Holder transfers
or assigns any of the Debentures to a party who or which would not be considered
such an affiliate,  such assignment shall be made subject to the transferee's or
assignee's specific agreement to be bound by the provisions of this Section 4(C)
as if such transferee or assignee were the original Holder hereof.

         (D) The Holder recognizes that the Company may be limited in the number
of shares of Common Stock it may issue by (i) reason of its  authorized  shares,
or (ii) the applicable rules and regulations of the principal  securities market
on  which  the  Common  Stock  is  listed  or  traded  (collectively,  the  "CAP
REGULATIONS").  Without  limiting the other provisions  hereof,  (i) the Company
will take all steps reasonably  necessary to be in a position to issue shares of
Common  Stock  on  conversion  of  the  Debentures  without  violating  the  Cap
Regulations  and (ii) if,  despite  taking such steps,  the Company still cannot
issue such shares of Common Stock  without  violating the Cap  Regulations,  the
Holder  of this  Debenture  (to the  extent  the  same can not be  converted  in
compliance with the Cap Regulations (an  "UNCONVERTED  DEBENTURE")),  shall have
the option,  exercisable in the Holder's sole and absolute discretion,  to elect
any one of the following remedies:

               (x) if permitted by the Cap  Regulations,  require the Company to
          issue shares of Common Stock in accordance  with such Holder's  Notice

                                       3

          of Conversion  relating to the  Unconverted  Debenture at a conversion
          purchase price equal to the average of the closing bid price per share
          of Common Stock for any five (5) consecutive  trading days (subject to
          the equitable  adjustments  for certain events  occurring  during such
          period as provided in this  Debenture)  during the sixty (60)  trading
          days immediately preceding the date of the Notice of Conversion; or

               (y) require the Company to redeem each Unconverted  Debenture for
          an amount (the "CAP REDEMPTION AMOUNT"), payable in cash, equal to:

                                    V        x       M
                                  -----
                                    CP

               where:

               "V" means the outstanding principal plus accrued interest through
          the  Cap  Redemption   Date  (as  defined  below)  of  an  Unconverted
          Debenture;

               "CP"  means  the  Conversion  Price  in  effect  on the  date  of
          redemption  (the "CAP REDEMPTION  DATE")  specified in the notice from
          the Holder electing this remedy; and

               "M"  means  the  highest  closing  ask price  during  the  period
          beginning on the Cap Redemption Date and ending on the date of payment
          of the Cap Redemption Amount.

The holder of an Unconverted  Debenture may elect one of the above remedies with
respect to a portion of such  Unconverted  Debenture  and the other  remedy with
respect to other portions of the Unconverted Debenture.

          (E) Anything herein to the contrary notwithstanding,  in the event the
Company  breaches  the  provisions  of Section 4(f) of the  Securities  Purchase
Agreement,  the  Conversion  Price  shall be  amended  to be equal to 90% of the
Conversion  Price  determined in accordance with Section 4(A) of this Debenture,
and the Holder may  require the Company to  immediately  redeem the  outstanding
portion of this Debenture in accordance with clause (y) of Section 4(D).


          (F) Any Debentures  not previously  converted as of the Maturity Date,
shall be deemed to be  automatically  converted,  without  further action of any
kind by the Company or any of its agents,  employees or  representatives,  as of
the Maturity  Date at the  Conversion  Price  applicable  on the  Maturity  Date
("MANDATORY CONVERSION").

     5.  REDEMPTION.  This  Debenture  can be redeemed for cash at any time,  in
whole or in part, by the Company. To redeem the Debenture,  the Company must (i)
send a  written  notice to the  Holder  not less than five (5) nor more than ten
(10) business days prior to the date on which it wishes to redeem the Debenture,
and (ii) pay the Holder  cash or  immediately  available  funds in the amount of

                                       4

115% times the  principal  amount of the  Debenture  then  outstanding  plus all
accrued but unpaid interest. If the Company does not pay the redemption price to
the Holder on or before the date of  redemption  specified  in the  notice,  the
Holder will have the right to deem such notice of redemption to be null and void
and the Company will lose its right to further redeem this  Debenture.  A holder
may convert all or any part of this Debenture up to the amount redeemed pursuant
to such notice at any time during the first five (5) business days following the
notice of redemption and without regard to the provisions of Section 4(C).

     6. Subject to the terms of the Securities Purchase Agreement,  no provision
of this Debenture shall alter or impair the obligation of the Company,  which is
absolute  and  unconditional,  to pay the  principal  of, and  interest on, this
Debenture at the time,  place,  and rate,  and in the coin or  currency,  herein
prescribed.  This Debenture and all other  Debentures now or hereafter issued of
similar terms are direct obligations of the Company.

     7. No  recourse  shall be had for the payment of the  principal  of, or the
interest  on, this  Debenture,  or for any claim based  hereon,  or otherwise in
respect hereof, against any incorporator,  shareholder,  officer or director, as
such,  past,  present or future,  of the Company or any  successor  corporation,
whether  by  virtue  of any  constitution,  statute  or rule  of law,  or by the
enforcement of any assessment or penalty or otherwise, all such liability being,
by the acceptance  hereof and as part of the consideration for the issue hereof,
expressly waived and released.

     8. If the Company merges or consolidates with another  corporation or sells
or transfers all or  substantially  all of its assets to another  person and the
holders  of the  Common  Stock are  entitled  to receive  stock,  securities  or
property in respect of or in exchange for Common  Stock,  then as a condition of
such  merger,  consolidation,  sale  or  transfer,  the  Company  and  any  such
successor,  purchaser or transferee  agree that the Debenture may  thereafter be
converted  on the terms and subject to the  conditions  set forth above into the
kind and amount of stock,  securities or property  receivable  upon such merger,
consolidation,  sale or  transfer  by a holder of the number of shares of Common
Stock into which this  Debenture  might have been converted  immediately  before
such merger, consolidation, sale or transfer, subject to adjustments which shall
be as nearly  equivalent  as may be  practicable.  In the event of any  proposed
merger,  consolidation  or sale or transfer of all or  substantially  all of the
assets of the  Company (a  "SALE"),  the Holder  hereof  shall have the right to
convert this  Debenture  by  delivering  a Notice of  Conversion  to the Company
within fifteen (15) days of receipt of notice of such Sale from the Company.  In
the event the Holder  hereof  elects not to convert,  the Company may prepay all
outstanding principal and accrued interest on this Debenture pursuant to Section
5 hereof, less all amounts required by law to be deducted,  upon which tender of
payment following such notice, the right of conversion shall terminate.

     9. If, for any reason,  prior to the conversion or redemption,  the Company
spins off or otherwise divests itself of a part of its business or operations or
disposes all of or a substantial  part of its assets in a transaction (the "SPIN
OFF") in which the Company  does not  receive  compensation  for such  business,
operations or assets,  but causes  securities  of another  entity (the "SPIN OFF
SECURITIES") to be issued to security  holders of the Company,  then the Company
shall cause (i) to be reserved Spin Off  Securities  equal to the number thereof
which  would have been issued to the Holder had all of the  Holder's  Debentures
outstanding  on the record date (the "RECORD DATE") for  determining  the amount
and  number  of Spin Off  Securities  to be issued to  security  holders  of the

                                       5

Company  (the  "OUTSTANDING  DEBENTURES")  been  converted  as of the  close  of
business on the trading day  immediately  before the Record Date (the  "RESERVED
SPIN OFF SHARES"),  and (ii) to be issued to the Holder on the conversion of all
or any of the  Outstanding  Debentures,  such  amount of the  Reserved  Spin Off
Shares equal to (x) the Reserved  Spin Off Shares  multiplied by (y) a fraction,
of which (I) the numerator is the principal amount of the Outstanding Debentures
then being  converted,  and (II) the denominator is the principal  amount of the
Outstanding Debentures.

     10.  If,  at  any  time  while  any  portion  of  this  Debenture   remains
outstanding, the Company effectuates a stock split or reverse stock split of its
Common  Stock or issues a dividend on its Common Stock  consisting  of shares of
Common Stock, the Conversion  Price shall be equitably  adjusted to reflect such
action. By way of illustration,  and not in limitation, of the foregoing: (i) if
the  Company  effectuates  a 2:1 split of its  Common  Stock,  thereafter,  with
respect to any  conversion  for which the  Company  issues the shares  after the
record date of such split,  the Conversion  Price shall be deemed to be one-half
of the  Conversion  Price  calculated  in  Section  4(A);  (ii)  if the  Company
effectuates a 1:10 reverse split of its Common Stock,  thereafter,  with respect
to any  conversion for which the Company issues the shares after the record date
of such reverse split,  the Conversion Price shall be deemed to be ten times the
Conversion Price calculated in Section 4(A); and (iii) if the Company declares a
stock  dividend  of one share of Common  Stock for every 10 shares  outstanding,
thereafter,  with  respect to any  conversion  for which the Company  issues the
shares after the record date of such  dividend,  the  Conversion  Price shall be
deemed  to be the  amount of the  Conversion  Price  calculated  in  Section  4A
multiplied  by a fraction,  of which the  numerator is the number of shares (10)
for which a dividend share will be issued and the  denominator is such number of
shares plus the  dividend  share(s)  issuable or issued  thereon  (11).

     11. All payments  contemplated hereby to be made "in cash" shall be made in
immediately  available  good funds in such coin or currency of the United States
of America as at the time of payment is legal  tender for  payment of public and
private debts.  All payments of cash and each delivery of shares of Common Stock
issuable to the Holder as contemplated hereby shall be made to the Holder at the
address last appearing on the Debenture Register of the Company as designated in
writing by the Holder from time to time;  except that the Holder can  designate,
by notice to the  Company,  a  different  delivery  address  for any one or more
specific payments or deliveries.

     12. The Holder of the  Debenture,  by acceptance  hereof,  agrees that this
Debenture is being  acquired for  investment  purposes and that such Holder will
not offer,  sell or otherwise  dispose of this Debenture or the Shares of Common
Stock issuable upon conversion thereof except under circumstances which will not
result in a  violation  of the Act or any  applicable  state Blue Sky or foreign
laws or similar laws relating to the sale of securities.

     13. This  Debenture  shall be governed by and construed in accordance  with
the  laws  of the  State  of  Delaware.  Each  of the  parties  consents  to the
jurisdiction  of the federal  courts whose  districts  encompass any part of the
City of Wilmington  or the state courts of the State of Delaware  sitting in the
City of Wilmington in connection  with any dispute  arising under this Agreement
and hereby  waives,  to the maximum  extent  permitted  by law,  any  objection,
including any  objection  based on FORUM NON  COVENIENS,  to the bringing of any
such proceeding in such  jurisdictions.  To the extent determined by such court,

                                       6

the  Company  shall  reimburse  the  Holder  for any  reasonable  legal fees and
disbursements  incurred by the Holder in  enforcement of or protection of any of
its rights under any of this Debenture.

     14. The following shall constitute an "Event of Default":

               a. The  Company  shall  default in the  payment of  principal  or
          interest on this Debenture and same shall continue for a period of ten
          (10) days; or

               b. Any of the  representations  or warranties made by the Company
          herein, in the Securities Purchase Agreement,  the Registration Rights
          Agreement  or  in  any  certificate  or  financial  or  other  written
          statements  heretofore  or  hereafter  furnished  by  the  Company  in
          connection  with the execution  and delivery of this  Debenture or the
          Securities  Purchase  Agreement  shall be false or  misleading  in any
          material respect at the time made; or

               c. The  Company  fails to issue  shares  of  Common  Stock to the
          Holder or to cause its Transfer  Agent to issue shares of Common Stock
          upon exercise by the Holder of the conversion  rights of the Holder in
          accordance with the terms of this  Debenture,  fails to transfer or to
          cause its  Transfer  Agent to transfer any  certificate  for shares of
          Common Stock issued to the Holder upon  conversion  of this  Debenture
          and  when  required  by  this  Debenture  or the  Registration  Rights
          Agreement,  and such transfer is otherwise  lawful, or fails to remove
          any  restrictive  legend or to cause its Transfer Agent to transfer on
          any  certificate  or any shares of Common  Stock  issued to the Holder
          upon  conversion  of  this  Debenture  as and  when  required  by this
          Debenture, the Agreement or the Registration Rights Agreement and such
          legend  removal  is  otherwise  lawful,  and any  such  failure  shall
          continue uncured for five (5) business days.

               d. The Company shall fail to perform or observe,  in any material
          respect, any other covenant, term, provision,  condition, agreement or
          obligation  of any  Debenture  in this series and such  failure  shall
          continue uncured for a period of thirty (30) days after written notice
          from the Holder of such failure; or

               e. The Company shall fail to perform or observe,  in any material
          respect,  any  covenant,  term,  provision,  condition,  agreement  or
          obligation of the Company under the Securities  Purchase  Agreement or
          the  Registration  Rights  Agreement and such failure  shall  continue
          uncured for a period of thirty (30) days after written notice from the
          Holder of such failure (other than a failure to cause the Registration

                                       7

          Statement to become  effective  no later than the  Required  Effective
          Date, as defined and provided in the Registration Rights Agreement, as
          to which no such cure period shall apply); or

               f. The Company  shall (1) admit in writing its  inability  to pay
          its debts  generally as they mature;  (2) make an  assignment  for the
          benefit of creditors or commence  proceedings for its dissolution;  or
          (3) apply for or consent to the  appointment of a trustee,  liquidator
          or  receiver  for its or for a  substantial  part of its  property  or
          business; or

               g. A trustee,  liquidator or receiver  shall be appointed for the
          Company or for a substantial  part of its property or business without
          its consent and shall not be  discharged  within sixty (60) days after
          such appointment; or

               h. Any governmental agency or any court of competent jurisdiction
          at the instance of any  governmental  agency  shall assume  custody or
          control of the whole or any  substantial  portion of the properties or
          assets of the Company  and shall not be  dismissed  within  sixty (60)
          days thereafter; or

               i. Any money judgment, writ or warrant of attachment,  or similar
          process in excess of Two Hundred  Thousand  ($200,000)  Dollars in the
          aggregate  shall be entered or filed against the Company or any of its
          properties  or  other  assets  and  shall  remain  unpaid,  unvacated,
          unbonded or  unstayed  for a period of sixty (60) days or in any event
          later  than  five (5) days  prior  to the  date of any  proposed  sale
          thereunder; or

               j.   Bankruptcy,   reorganization,   insolvency  or   liquidation
          proceedings or other  proceedings  for relief under any bankruptcy law
          or any law for the relief of debtors shall be instituted by or against
          the Company  and, if  instituted  against  the  Company,  shall not be
          dismissed or stayed within sixty (60) days after such  institution  or
          the Company shall by any action or answer  approve of,  consent to, or
          acquiesce in any such  proceedings  or admit the material  allegations
          of, or default in answering a petition  filed in any such  proceeding;
          or

               k. The Company shall have its Common Stock  suspended or delisted
          from an exchange or over-the-counter market from trading for in excess
          of five (5) trading days; or

               l. The Company fails to file the  Registration  Statement  within
          sixty  (60)  days  following  the  Closing  Date  or the  Registration

                                       8

          Statement is not  declared  effective  within one hundred  fifty (150)
          days following the Closing Date.

Then, or at any time  thereafter,  and in each and every such case,  unless such
Event of Default  shall have been waived in writing by the Holder  (which waiver
shall not be deemed to be a waiver of any  subsequent  default) at the option of
the Holder and in the Holder's  sole  discretion,  the Holder may consider  this
Debenture immediately due and payable,  without presentment,  demand, protest or
notice of any kinds, all of which are hereby expressly  waived,  anything herein
or in any note or other instruments  contained to the contrary  notwithstanding,
and the Holder may  immediately  enforce any and all of the Holder's  rights and
remedies provided herein or any other rights or remedies afforded by law.

     15. Nothing  contained in this  Debenture  shall be construed as conferring
upon the  Holder  the right to vote or to  receive  dividends  or to  consent or
receive notice as a shareholder in respect of any meeting of shareholders or any
rights  whatsoever  as a  shareholder  of the Company,  unless and to the extent
converted in accordance with the terms hereof.

     16. In the event for any  reason,  any  payment by or act of the Company or
the Holder  shall  result in payment of interest  which  would  exceed the limit
authorized  by or be in violation of the law of the  jurisdiction  applicable to
this  Debenture,  the  obligation of the Company to pay interest or perform such
act or requirement  shall be reduced to the limit  authorized under such law, so
that in no event  shall  the  Company  be  obligated  to pay any such  interest,
perform any such act or be bound by any  requirement  which would  result in the
payment  of  interest  in excess of the  limit so  authorized.  In the event any
payment by or act of the Company  shall  result in the  extraction  of a rate of
interest in excess of a sum which is lawfully collectible as interest, then such
amount (to the extent of such excess not returned to the Company) shall, without
further  agreement or notice between or by the Company or the Holder,  be deemed
applied to the payment of principal,  if any, hereunder immediately upon receipt
of such excess funds by the Holder, with the same force and effect as though the
Company had specifically  designated such sums to be so applied to principal and
the Holder had agreed to accept such sums as an interest-free prepayment of this
Debenture.  If any part of such excess remains after the principal has been paid
in full, whether by the provisions of the preceding sentences of this Section 16
or otherwise,  such excess shall be deemed to be an interest-free  loan from the
Company to the Holder,  which loan shall be payable  immediately  upon demand by
the  Company.  The  provisions  of this  Section 16 shall  control  every  other
provision of this Debenture.

                                       9

     IN WITNESS  WHEREOF,  the  Company has caused  this  instrument  to be duly
executed by an officer thereunto duly authorized.


     Dated: __________________, 1999

                                                    LIGHTPATH TECHNOLOGIES, INC.

                                                    By:
                                                        ------------------------

                                                        ------------------------
                                                              (Print Name)

                                                        ------------------------
                                                                 (Title)

                                       10

                                    EXHIBIT A


     NOTICE OF CONVERSION

     (To be Executed by the Registered Holder in order to Convert the Debenture)



     The undersigned hereby irrevocably elects to convert $ ________________  of
the principal  amount of the above Debenture No. ___ into Shares of Common Stock
of LightPath  Technologies,  Inc. (the  "COMPANY")  according to the  conditions
hereof, as of the date written below.


         Conversion Date*
         -----------------------------------------------------

         Applicable Conversion Price
         -----------------------------------------------------


         Signature
         -----------------------------------------------------
                                [Name]

         Address:
         -----------------------------------------------------

         -----------------------------------------------------

     * This  original  Debenture  must be  received  by the Company by the fifth
business date following the Conversion Date.