The Development of Various Types of Glass. Part V. A Comparison of the Soda-Lime-Silica and the Potassium

JSGT 1920 V04 T071-T107 (37 pages)

Glasses of the above types having been treated-separately, it remains to correlate the results obtained and deal with their likenesses and differences. All these glasses can be represented by the general molecular formula 100SiO₂.xR₂O.yCaO, where R₂O represents the oxide of sodium, the oxide of potassium or mixtures of these two alkaline oxides. The nature of R₂O determines in no inconsiderable way the properties of the glass containing it, and there are widespread differences in the relative effects of Na₂O or K₂O in glasses of this type. The substitution of the Na₂O in glass by K₂O, whether viewed from the point of view of equal molecular proportion or equal percentage proportion by weight, does not result in a glass of exactly similar properties.

C. J. Peddle