Carrier Concentrations and Relaxation Spectroscopy: New Information from Scaling Properties of Conductivity Spectra in Ionically Conducting Glasses

A new kind of scaling analysis for the conductivity spectra of glasses without any arbitrary parameters is presented. By applying this method to sodium borate glasses of different compositions, we find strong indications for the existence of a universal ionic relaxation process as well as for a strong electrolyte behavior. Our results enable us to show that the often used electric modulus formalism is misleading when relaxation mechanisms on a microscopic level are concerned. A more meaningful discussion can be based on the log-log dependence of the conductivity on frequency.