Chapter 6: Monovalent Cations in Germanate Glasses and Melts Check Access

The alkali germanate glasses are the most thoroughly studied germanate glasses. The presence of maxima and/or minima in the trends of many properties of these glasses as a function of alkali concentration gave rise to the term “germanate anomaly” to indicate that the properties are not monotonic functions of alkali content. The effect of alkali concentration on a wide range of glass properties is considered in this chapter, along with discussions of the compositions at which the various germanate anomalies occur. Since values for many of the properties of these glasses vary among reports, best values have been determined for the density, refractive index, electrical conductivity, alkali diffusivity, and glass transformation temperature. The limited property data available for other monovalent oxides, called “pseudoalkali oxides” (Cu₂O, Ag₂O, and Tl₂O) are also presented.