An initial study was made of the frequency-dependent conductivity spectra of glassy 0.1Li2O-0.1Na2O-0.1K2O-0.7B2O3 over a wide temperature range. The conductivity isotherms of the glasses exhibited a transition from their direct-current plateaux into a dispersive regime where the conductivity increased continuously with frequency; tending towards a linear frequency dependence at sufficiently low temperatures. At a given temperature, the direct-current conductivities of glassy 0.1Li2O-0.1Na2O-0.1K2O-0.7B2O3 were much lower than those of 0.3[xM2O(1−x)Me2O]-0.7B2O3 (M–Me = Li–Na, Li–K, and Na–K) and 0.2[xLi2O(1−x)Na2O]-0.8B2O3 glasses. The direct-current conductivity activation energy of glassy 0.1Li2O-0.1Na2O-0.1K2O-0.7B2O3 was higher than those of 0.3[xM2O(1−x)Me2O]-0.7B2O3 and 0.2[xLi2O(1−x)Na2O]-0.8B2O3 glasses with x = 0, 0.2, 0.4, 0.6, 0.8 or 1. The experimental results were interpreted in terms of the dynamic structure model of Bunde, Ingram and Maass. On the basis of the results, it was predicted that mixed alkali glasses with 3 types of cation exhibited a stronger mixed-alkali effect, in physical quantities related to ion transport, than did glasses with only 2 types of cation.

Ionic Conductivity of Glasses with Two and Three Types of Alkali Ions. Y.Gao, C.Cramer: Solid State Ionics, 2005, 176[9-10], 921-7