Multinuclear NMR investigation of temperature effects on structural reactions involving non-bridging oxygens in multicomponent oxide glasses

The energetics of structural mechanisms involving inter-conversions among oxygen species dictate structure and properties of oxide glasses. We explored the change in boron coordination as a function of fictive temperature in glasses containing Zr and/or Na. There was lower boron coordination in the Zr-containing glass, and there was less decrease in boron coordination with temperature. We relate this difference to changes in the energetics of Zr-O-Si and Na-O-Si linkages. Furthermore, we varied fictive temperature to explore the distribution of non-bridging oxygens (NBO) on Al and Si in a Ca aluminosilicate and a Y aluminosilicate. As temperature increased, Al-NBO% increased. We attribute this change with temperature to differences in the energetics of Si-NBO and Al-NBO, which result in a strong preference for Si-NBO that is predicted to persist over a wide temperature range.