Abstract
The scaling properties of the ac conductivity of ion-conducting glasses have, in the last several years, led to considerable revision of our understanding of microscopic ion dynamics. Although the notion that frequency dependent dispersion of the ac conductivity is evidence for correlated (as opposed to purely random) ion motions remains intact, notions about the role of ion-ion interactions as a source for the correlated behavior are clearly inconsistent with the scaling properties of the ac conductivity. Instead, certain systematic variations in the dispersion highlight the possible importance of the cation's local structural environment to influence the correlated motion. Here, I review some of the recent scaling ideas and their consequences with the goal of providing the casual impedance spectroscopist a set of practical guidelines for how scaling analyses may help in understanding ion conductivity measurements.