Optical properties of a liquid-crystalline random copolyester

We have investigated the optical properties of Vectra A910, a commercially produced liquid-crystalline copolyester consisting of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid subunits. The polymer is highly fluorescent in the near UV with an emission maximum at 428 nm (2.90 eV) and an excitat ion maximum at 376 nm (2.66 eV). The time-resolved fluorescent decays at ro om temperature were found to fit stretched exponential decays. Furthermore, the fluorescence kinetics were found to be highly dependent upon the emiss ion wavelength. These results are consistent with the disorder from the ran dom nature of the copolymer.