In situPoling and Orientation Stability of Chromophore-bearing Ladderlike Polysiloxanes

Abstract

A new, specially designed nonlinear optical (NLO) polymer is composed of ladderlike polysilsesquioxane as a backbone and “side-on or end-on” fixed stilbene chromophores. In-situ poling was carried out simultaneously during film formation via solvent evaporation and crosslinking which was caused by sequential hydrolysis and condensation of remained Si-H groups on macromolecules. The dipolar orientation after poling is described by an order parameter Φ which was measured using an original linear optical technique–UV dichroism. Orientation order and its decay are influenced by chromophore loading, crosslinking degree and poling condition. Compared with corresponding single chain polymers, a poled thin film of ladderlike NLO polymers demonstrates more stable poling-induced orientation.