Viscoelasticity and Birefringence of Polycarbonate Derivatives.

The complex Young's modulus and the complex strain-optical coefficient of two series of polycarbonate derivatives were measured around the glass transition zone to investigate the molecular structure-property relationships. The data were analyzed with the modified stress-optical rule: The complex Young's modulus was separated into two component function, R and G. Main chain flexibility and the intrinsic birefringence were estimated from the R component. It was found that the main flexibility was insensitive to the substitution on phenylene groups or propylene groups while the intrinsic birefringence could be significantly reduced.