Static and dynamic Kerr-effect studies of glycerol in its highly viscous state

Abstract

Static and dynamic Kerr-effect studies have been made for glycerol in the range 205–255 K. The static measurements indicate extensive association of the molecules and that this increases with decreasing temperature, in accord with the results of dielectric studies. The dynamic Kerr effect shows one, near single-relaxation time, process at all temperatures with the rise and decay correlation times being related according to τK,r=(1.45 ± 0.20)τK,d. Dielectric relaxation measurements made concurrently with the Kerr-effect relaxation measurements show that τD≈(½)τK,d. The relationships between the relaxation of the Kerr effect, dielectric ultrasonic and dynamic light-scattering processes are discussed in terms of the structural relaxation mechanism and cross-correlation functions which appear for each technique. The Kerr-effect relaxation is slower than that for dielectric relaxation at a given temperature which is, in turn, slower than that for the light-scattering relaxation. The importance of mixed Rayleigh and Mountain relaxation for the latter is discussed in relation to the theory of Demoulin and co-workers.