Dynamic Exchange Effects in Broadband Dielectric Spectroscopy

Abstract

We calculate the consequences of molecular exchange between two states with different relaxation rates in dielectric spectra. In a critical range where exchange rates are of the order of the relaxation rates, both individual processes show apparently increased relaxation frequencies, and the slower process gains intensity from the faster. In the fast exchange limit, only one process with averaged relaxation rate remains. The model is well suited to describe the effects in the dielectric spectra of a microconfined glass-forming liquid (salol) in porous glasses.