An Apparatus for Dynamic Birefringence Measurements

Abstract

An apparatus was constructed for simultaneous measurements of the dynamic birefringence and the complex Young's modulus. The frequency range was 1-200 Hz. The instrument was calibrated with a polybutadiene film, for which the stress optical law was expected to hold well. The stress optical coefficient estimated by dynamic birefringence measurement was consistent with the result of the static measurement. The stress-optical law did not hold valid for a polystyrene film containing 5 wt% dibutyl phtalate in the glass-to-rubber transition region.