Nonlinear optical properties of some side chain copolymers based on benzoxazole containing chromophores

Acrylate-methylmethacrylate copolymers have been synthesized for nonlinear optical applications. Acrylate monomer units are characterized by the prese nce in the side chain of phenylbenzoxazole groups containing electron donor -electron acceptor substituents. The phase behavior of all polymers has bee n investigated by DSC, X-ray diffraction and polarizing microscopy: two of them exhibit liquid crystalline behavior of smectic type. For four polymers , nonlinear optical properties have been examined by second harmonic genera tion measurements on thin films (similar to 1 mu m thickness) electrically poled by corona discharge. Second order susceptibility coefficients d(33) a nd average relaxation times <tau >, relative to the time stability of the c hromophore poling, have been measured. (C) 1999 John Wiley & Sons, Inc.