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 presence in the side chain of phenylbenzoxazole groups containing electron donor-electron acceptor substituents. The phase behavior of all polymers has been 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 generation measurements on thin films (similar to 1 mu m thickness) electrically poled by corona discharge. Second order susceptibility coefficients d(33) and average relaxation times <tau >, relative to the time stability of the chromophore poling, have been measured. (C) 1999 John Wiley & Sons, Inc.