Piezoelectrically induced electro-optical effect and dipole orientation measurement in undoped amorphous polymers

Abstract

Fabry-Perot interferometry is used to study the electro-optical properties of poled poly(methyl methacrylate) and poly(styrene acrylonitrile) polymeric films. The apparent electro-optical effect is shown to be proportional to the piezoelectric coefficients of the film and to the (cos phi ) dipole order parameter. For poly(styrene acrylonitrile), this technique gives piezoelectric coefficients close to those derived from dielectric measurements and thermodynamic considerations. Direct electro-optical activity measurement is used to record the dipole orientation step response function in these two glassy matrices at various temperatures. For both polymers these functions are similar at a given difference in temperature below the glass transition temperature and are non-exponential.