The Influence of Some Metal Ions on the Devitrification of Glasses

JSGT 1951 V35 T284-T288

By means of X-ray spectrometer diagrams the crystallisation of glasses containing about 95 mol% SiO₂ and about 5 mol% of Li₂O, Na₂O, K₂O, BeO, MgO, CaO, BaO or ZnO at 1200° has been studied. The univalent ions are shown to promote the formation of tridymite from initially formed cristobalite. The glasses with bivalent ions devitrify by formation of cristobalite. A number of these ions influence the crystallisation in such a way that it starts with the temporary formation of quartz. Probably this is due to a direct influence of these ions on the glass and not on the transformation of the crystalline phases.

G. D. Rieck & J. M. Stevels