α-relaxation near the liquid-glass transition

Abstract

The dynamics of alpha -relaxation of undercooled fluids close to the liquid glass transition is analysed within the recently developed mode coupling theory. Asymptotic expansions for the master functions are obtained from the scaling equation for short and for long times. The Cole-Cole expression is found as the simplest extrapolation of the short time results predicted by the scaling equation, and it is in turn related to Kohlrausch relaxation preceded by beta -relaxation processes. A formula for an effective Kohlrausch exponent is derived. Detailed numerical results for alpha -relaxation curves are presented for a schematic model which are compared with the Cole-Cole and Kohlrausch fits as well as with some experimental data.