Search

Translational diffusion coefficients D of photochronic dye molecules have been measured by forced Rayleigh scattering in polymer diluent systems at compositions from pure polymer to pure diluent. D could be measured down to below the glass transition temperature Tg. In the pure diluent, D(Tg) was found typically about two decades below that in the pure polymer but still far above the Stokes-Einstein prediction extrapolated from high temperatures. Some experimental results are in contrast with predictions from free-volume theory. [ABSTRACT FROM AUTHOR]