Kerr effect and electrostriction in thin polymeric films. Application to polysilane films

The attenuated total reflection method is used for studying the quadratic electrooptic effect (χ (3)) and the electrostriction in a thin film of a centrosymmetric polymer (Polysilane). We develop a new method for measuring the anisotropy of these effects and for determining the direct Kerr effect and the indirect one, due to the mechanical strains. We give some preliminary results about the observation of quadratic effects in non centrosymmetric materials which exhibit a large χ (2).