DYNAMIC EXCHANGE EFFECTS IN BROAD-BAND DIELECTRIC-SPECTROSCOPY

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, b oth individual processes show apparently increased relaxation frequenc ies, and the slower process gains intensity from the faster. In the fa st exchange limit, only one process with averaged relaxation rate rema ins. The model is well suited to describe the effects in the dielectri c spectra of a microconfined glass-forming liquid (salol) in porous gl asses.