Evidence for a universal crossover behaviour of the dynamic glass transition

Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87 Fachgruppe VI.3 - D-12205 Berlin, Germany

Received: 18 July 2001
Accepted: 5 October 2001

Abstract

By measuring the complex dielectric function over 15 decades of frequency, the temperature dependence of the mean relaxation time and of the dielectric strength is evaluated for six low-molecular-weight glass-forming liquids and one polymeric melt. For the first time it could be shown that a universal correlation exists between both these quantities with a sharp defined crossover behaviour in the frequency range between 10⁷ and 10⁸ . So two dynamical different regions of the α-relaxation can be distinguished non-ambiguously.