FORM OF BRIDGE LOAN NOTE

$1,600,000                                                  September __, 1997
                                                            New York, New York


            SONICS & MATERIALS,  INC., a Delaware  corporation  (the "Company"),
for  value  received,  hereby  promises  to pay to the  order of BROWN  BROTHERS
HARRIMAN & CO. (the  "Lender") the  principal  amount of ONE MILLION SIX HUNDRED
THOUSAND DOLLARS ($1,600,000) on the dates and in the principal amounts provided
in the Credit  Agreement  referred to below.  The Company  also  promises to pay
interest on the unpaid  principal amount hereof from time to time outstanding at
the rate  and on such  dates  as  provided  in the  Credit  Agreement.  All such
principal and interest  shall be payable in lawful money of the United States of
America in same day funds at the office of the Lender.

            This  Note  is the  Bridge  Loan  Note  referred  to in  the  Credit
Agreement dated of even date hereof (the "Credit Agreement") between the Company
and the Lender, and is entitled to the benefits thereof.  Capitalized terms used
but not defined herein have the meanings specified in the Credit Agreement.

            The  Lender is hereby  authorized  by the  Company to endorse on the
schedule (or a continuation  thereof)  attached  hereto,  the date and amount of
each payment or  prepayment  of  principal  of such Bridge Loan  received by the
Lender,  provided that any failure by the Lender to make any such endorsement or
any error  therein  shall not affect the  obligations  of the Company  under the
Credit  Agreement or this Note in respect of the Bridge Loan  evidenced  hereby.
This Note is subject to prepayment  and its maturity is subject to  acceleration
upon the terms provided in the Credit Agreement.

            The Company hereby waives presentment,  demand, protect or notice of
any kind in connection with this Note.

            THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE  WITH THE
LAWS OF THE STATE OF NEW YORK.

                              SONICS & MATERIALS, INC.


                              By:  ______________________________
                                    Name:
                                    Title:


<PAGE>


                                   Schedule


Payments or
Prepayments of                      Balance                       Notation
Principal                           Outstanding                   Made By


<PAGE>


                               BRIDGE LOAN NOTE

$1,600,000                                                  September __, 1997
                                                            New York, New York


            SONICS & MATERIALS,  INC., a Delaware  corporation  (the "Company"),
for  value  received,  hereby  promises  to pay to the  order of BROWN  BROTHERS
HARRIMAN & CO. (the  "Lender") the  principal  amount of ONE MILLION SIX HUNDRED
THOUSAND DOLLARS ($1,600,000) on the dates and in the principal amounts provided
in the Credit  Agreement  referred to below.  The Company  also  promises to pay
interest on the unpaid  principal amount hereof from time to time outstanding at
the rate  and on such  dates  as  provided  in the  Credit  Agreement.  All such
principal and interest  shall be payable in lawful money of the United States of
America in same day funds at the office of the Lender.

            This  Note  is the  Bridge  Loan  Note  referred  to in  the  Credit
Agreement dated of even date hereof (the "Credit Agreement") between the Company
and the Lender, and is entitled to the benefits thereof.  Capitalized terms used
but not defined herein have the meanings specified in the Credit Agreement.

            The  Lender is hereby  authorized  by the  Company to endorse on the
schedule (or a continuation  thereof)  attached  hereto,  the date and amount of
each payment or  prepayment  of  principal  of such Bridge Loan  received by the
Lender,  provided that any failure by the Lender to make any such endorsement or
any error  therein  shall not affect the  obligations  of the Company  under the
Credit  Agreement or this Note in respect of the Bridge Loan  evidenced  hereby.
This Note is subject to prepayment  and its maturity is subject to  acceleration
upon the terms provided in the Credit Agreement.

            The Company hereby waives presentment,  demand, protect or notice of
any kind in connection with this Note.

            THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE  WITH THE
LAWS OF THE STATE OF NEW YORK.

                              SONICS & MATERIALS, INC.


                              By:  ______________________________
                                    Name:
                                    Title:


<PAGE>


                                   Schedule


Payments or
Prepayments of                      Balance                       Notation
Principal                           Outstanding                   Made By