Influential role of Al2O3 and B2O3 on selenium ruby glass

This paper represents the results of investigations on the melting of selenium ruby glass, particularly on the effect of Al2O3 and B2O3 on ruby colour. A glass of base composition (wt. %) SiO2 65.0, Na2O 15.5, K2O 5.3, ZnO 12.0, B2O3, 1.0, CdS 0.6, Se 0.6 has been chosen for these studies. In this study Al2O3 and B2O3 are systematically substituted for Na2O in small amounts from 0.5 to 3.0 %. Effects of these substitutions on melting, refining, colour, striking temperature etc. have been recorded. Transmittance of some representative samples has been determined. Glasses containing Al2O3 1.5 to 2.5 and B2O3 2 to 3.0 % have been found suitable for the development of red signal glass. Pilot plant meltings also gave satisfactory results.