On the Structure of Silicate Glasses

The diagram of the molecular refractien of Na 2 O-SiO 2 glasses vs. composition (Na 2 O mol%= x ) is found to be linear with breaks at x =0.231, 0.333, 0.428 and 0.474. Analysing this fact, it is concluded that at the latter three breaks the glass has the similar local arrangement of SiO 4 tetrahedra as the silicate crystals do, which was found before by the author on X-ray and viscosity. The break at x =0.231 is briefly discussed. By the introduction of Na 2 O or other oxides into SiO 2 glass, “ solvation ” takes place, and also “ solvation in refractivity ”–dec rease of refractivity of SiO 4 tetrahedra–takes place. These effects by the various metal ions are summarized and the characteristics of ions in gases or aqueous solutions are found to be preserved to some extent also in the silicate glasses.