Critical Analysis of Glass Stability Parameters and Application to Lithium Borate Glasses

We reevaluated nine parameters of glass stability (GS) against crystallization determined from differential scanning calorimetry (DSC) experiments to predict the glass-forming ability (GFA) of oxide liquids on cooling. Then, borate glasses were prepared and tested, covering the Li(2)O-B(2)O(3) system with 20.0-66.7 mol% lithia. The glasses were prepared from both commercial chemical and powders, obtained by a solution method. The GS parameters were calculated using characteristic glass transition, crystallization, and melting peaks of DSC thermograms. We found that seven stability parameters give similar trends for compositions up to 33.3 mol% lithia, where, as we expected, GS significantly decreases with lithia content. Thereafter, up to 66.7 mol% lithia, GS shows a broad shallow maximum, but is approximately constant indicating that, surprisingly, composition does not significantly affect the GFA in this wide compositional range. This result qualitatively agrees with our successful experience of preparing glasses with compositions up to 74 mol% lithia and corroborates the adequacy of simple DSC tests to comparatively gauge the GS and GFA of glass-forming liquids.