Properties and Structure of Glasses in the Binary Systems Alkali—TiO 2

Glasses corresponding to mole formulas R 2 TiO 3 and R 2 Ti 2 O 5 were prepared in 1‐ to 5‐g quantities by quenching in a platinum crucible. K 2 O, Rb 2 O, and Cs 2 O formed fairly stable glasses with TiO 2 . On heat treatment, these glasses nucleated readily and formed opal‐like glasses. Li 2 O and Na 2 O, however, did not form glasses with TiO 2 in 1‐g quantities. Hygroscopicity increased with the alkali content and decreased with the increase in TiO 2 concentration. The refractive indices of the glasses ranged from 1.66 to 1.90. These facts indicate that TiO 2 is a glass former in its own right and that Ti 4+ exists in sixfold coordination in these glasses.