Spontaneously opacifying glass compositions with low volume relaxation

摘要

Spontaneous opal glass compositions of the fluoride opacified soda-boro-aluminosilicate type which display a low volume relaxation together with good opacity, resistance to development of surface slipperiness and odour under humid conditions, and low batch cost, the glass compositions comprising:said components constituting at least 99.5% of the composition, the balance, if any, comprising fining agents and/or colourants. By reason of the unusual thermal expansion characteristics of this glass, it can be formed into articles and decorated by economical mass production techniques, with a low breakage rate even if poorly annealed.