Ultrasonic Shear and Longitudinal Measurements in Aqueous Glycerol

Abstract

Glycerol—water mixtures containing up to 68 mole % water were subjected to ultrasonic shear and longitudinal measurements over the temperature range +50° to −120°C. The low-frequency absorption coefficient and the velocity of sound were measured at 25°C for various glycerol—water mixtures from pure glycerol to pure water. The results demonstrate the existence of low- and high-frequency limiting compressional moduli and a high-frequency limiting shear modulus. The relaxational moduli were found to be linear with temperature for each concentration, and also were linearly dependent on water content. The width of the distribution of relaxation times was found to be independent of water content up to 68 mole %. This result fails to support Frohlich's model for the origin of the distribution of relaxation times. Estimated values of the relaxation parameters of water were obtained from the data. Those which were obtained by extrapolation appear to be reasonable when compared with theoretically obtained values.