Thermally Stimulated Currents and Alkali-Ion Motion in Silicate Glasses

The thermally stimulated polarizatioddepolarization (TSPC/TSDC) current technique is used to investigate alkali-ion motion in silicate glasses. lbo TSDC peaks are observed in all these glasses along with the dc conduction current at high temperatures. The low-temperature TSDC peak magnitude is essentially constant, but the second TSDC peak magnitude varies with the type of alkali ion present in these glasses. Based on a proposed model, the two TSDC peaks are interpreted in terms of the localized alkali-ion motion around the nonbridging oxygen ion and through the limited conduction pathways, respectively.