The conductivity of ternary glass compositions was studied in the solid and liquid states. Below the glass transition temperature, Ca migration could be well described by an Arrhenius law and was markedly affected by the non-bridging O content. A rapid enhancement of the conductivity occurred in glasses which contained a non-bridging O content of more than 30 to 35%. This corresponded to a percolation threshold. Above the glass transition temperature, the temperature dependence of the conductivity was better described by a Vogel-Tammann-Fulcher law and the non-bridging O content was no longer the important parameter. In the molten state, the network - characterised by the silica content - became the main parameter which governed the temperature dependence of the conductivity.

Influence of the Network on Conductivity in Ternary CaO-Al2O3-SiO2 Glasses and Melts. G.Gruener, D.De Sousa Meneses, P.Odier, J.P.Loup: Journal of Non-Crystalline Solids, 2001, 281[1-3], 117-24