Dielectric spectroscopy of glass-forming materials: α-relaxation and excess wing

Abstract

Abstract Molecular kinetics in glass-forming materials is strange in many respects. Most famous is the structural α-relaxation with its non-Debye behavior and non-Arrhenius temperature dependence of the relaxation rate. But also the processes beyond the α-relaxation, like excess wing or the fast processes in the ns–ps regime are unusual and in the focus of current experimental and theoretical investigations. In the present work, we show dielectric spectra of several prototypical glass-formers, including isolating dipolar and ionically conducting materials. By covering a broad frequency range that allows the detection of all the dynamic processes governing glassy dynamics, we will give an overview over the rich dynamical behavior of glass-forming materials. Especially we will concentrate on the α-process and the excess wing and discuss various phenomenological and theoretical approaches of these phenomena.