Depolarized Rayleigh spectroscopy of polystyrene near the glassndash;rubber relaxation

摘要

Depolarized Rayleigh scattering in polystyrene near the glassndash;rubber relaxation is studied using photon correlation spectroscopy. The observed correlation functions cannot be fit to a single exponential decay, but the empirical formCH(t)minus;1=dgr;+Athinsp;explsqb;minus;2 (t/tgr;)bgr;rsqb; describes the results very well. Average relaxation times lang;tgr;rang;= (tgr;/bgr;) Ggr; (1/bgr;) are determined from 100 to 130deg;C. The apparent activation energy for the change of lang;tgr;rang; with temperature is over 80 kcal/mole. Depolarized Rayleigh spectroscopy should prove to be a very useful tool in the study of relaxation behavior in polymers.