Temporal stability of second-order optical non-linearities depending on non-linear optically active groups of polyesters

Abstract

Four types of non-linear optical (NLO) polyesters with the same main chain and with different NLO-active groups have been synthesized. Second-order NLO properties of the corona-poled polyesters are studied by the second-harmonic generation (SHG) method. The structure of the NLO-active group affects not only the magnitude of the SHG coefficient (d ₃₃ ) but also the temporal stability of d ₃₃ . Though all the polyesters show nearly the same glass transition temperature, the polyesters having NLO-active groups with larger dipole moments show better temporal stability, suggesting that the dipole moment has a significant effect on temporal stability.