The effect of cation substitutions on structure and thermal properties of lithium disilicate glass with 1 mol% of P2O5 was investigated by DSC and solid-state NMR spectroscopy. The rationale was to understand how the nature of the nucleating phosphate phase changes with various elemental substitutions. Three series of glasses with up to 9% mol of sodium, potassium and zinc oxides substituted for lithia were prepared. Additionally, the crystallised glasses were characterised by the powder x-ray diffraction. Sodium substitution reduces the glass transition temperature, Tg, of the disilicate glass. Similar changes were observed on potassium substitution but he effect was smaller than in the sodium substituted by sodium but not by potassium nor zinc ions as shown by 31P magic angle spinning nuclear magnetic resonance (MAS-NMR).
