Topological constraint model of high lithium content borate glasses

Lithium borate glasses exhibit the “boron anomaly” and clustering of the lithium ions. Bødker et.al (Bødker, Mauro, Youngman, & Smedskjaer, 2019) predicted the Tg using statistical mechanics and topological constraint theory (TCT) over a wide range of contents (to 65 mol% Li2O). Although Bødker's model predicted the fraction of the structures present, this paper examines the linkage between intermediate-range structures and properties of the glasses. Tg was found using TCT with the structural model of Feller, Dell, and Bray (Feller, Dell, Bray, 1982). The topology of the intermediate-range structure was related to rigidity, and to lithium clustering.