Relationship between electrical melt conductivity and alkali content in multicomponent glass systems

The melt conductivities of 43 multicomponent glasses containing up to 15 different oxides were measured. These glasses are all borosilicate oxide glasses with less than 4 mol% anions. For the 43 glasses examined, the total alkali content is found to be a good predictor of their electrical melt conductivity. The correlation of alkali content to melt conductivity is stronger for 5-6 component glass systems than for a 15 component glass system and the correlation improves if all the glasses have enough alkaline earth to complex with the trivalent cations in the glass structure, leaving the alkali cations essentially free to conduct. This study shows that despite the complexity of multicomponent glass systems, for a wide range of borosilicate glasses, total alkali content can be used to predict electrical conductivity of glass melts from about 1000-1200 degrees C.