Description and analysis of electrical relaxation data for ionically conducting glasses and melts

In recent years there has arisen considerable controversy and some confusion with regard to analysis and interpretation of electrical relaxation data for ionically conducting glasses and melts. For example, there are questions as to whether the data are better described using the electric modulus formalism with a KWW distribution of relaxation times or by using a Jonscher power law fit to the frequency dependent electrical conductivity. This topic is reviewed and discussed, with some emphasis placed on the degree to which information on the electrical relaxation mechanisms and the microscopic sources of nonexponential relaxation can be extracted from data presentation and analysis using the electric modulus formalism with a well behaved electric field relaxation function.