Glass Formation and Recrystallization in the Lithium Metasilicate Region of the System Li 2 O–Al 2 O 3 –SiO 2

The stability of the vitreous state in the lithium metasilicate region of the system Li 2 O–Al 2 O 3 –SiO 2 was found to be a function of the concentration of lithia. The higher the lithia content, the less stable was the glass. The devitrification of glasses in this system was studied. In addition to the phases present at or near the liquidus, it was found that the β ‐eucryptite– β ‐quartz solid solution phase was metastable over most of the region. The Li 2 O–SiO 2 , β ‐Li 2 O–Al 2 O 3 –4SiO 2 solid solution, β ‐Li 2 O–Al 2 O 3 –2SiO 2 solid solution triple point was estimated to be near 62.5% SiO 2 , 17% Al 2 O 3 , and 20.5% Li 2 O (by weight). The thermal expansions of bodies in this region were measured and the values obtained are explained in terms of the phases present.