Enhanced second-harmonic response and stability of corona-poled guest?host polycarbonate thin films

Abstract

Second-harmonic generation and spectroscopic absorption measurements were made to study the non-linear optical and stability properties of guest/host polycarbonate thin films in which the guest chromophores were oriented by corona poling. Optimum poling conditions were achieved at temperatures less than the glass-rubber transition temperatures. Stabilized order parameters as high as 0.23 and retention of orientational order as high as 86% were found. Stable, resonance-enhanced, values of the non-linear optical coefficient d33, for the fundamental of 1.064 Μm, were as high as 31 pm V−1. This value is over four times that predicted by a simple thermodynamic model for isotropic materials. Hydrogen bonding between the guest and polycarbonate is proposed to account for the high d33 coefficients and long-term stability of the films.