Impulsive stimulated light scattered from glass-forming liquids. II. Salol relaxation dynamics, nonergodicity parameter, and testing of mode coupling theory

Abstract

Impulsive stimulated light scattering was used to investigate structural relaxation dynamics of the organic glass-former salol. Relaxation dynamics on ns–ms time scales are monitored in the 238.7–280.5 K temperature range and found to be described well by the Kohlrausch–Williams–Watts relaxation function. The nonergodicity parameter fq of mode-coupling theory (MCT) in the limit of the small wave vector q is evaluated. Its temperature dependence shows a square-root cusp at a crossover temperature of Tc=266 K, consistent with neutron scattering measurements at high q and with light scattering results. This supports the MCT prediction of a cusp in fq(T) at a q-independent temperature.