Nonlinear Optical Properties of Some Side Chain Copolymers Based on Benzoxazole Containing Chromophores

Acrylate-methylmethacrylate copolymers have been synthesized for non- linear 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 (ca 1 micron thickness) electrically poled by corona discharge. Second order susceptibility coefficients d33 and average relaxation times ͗<t>, relative to the time stability of the chromophore poling, have been measured.