Changes in the Indices of Refraction and Liquidus of a Barium Crown Glass Produced by the Partial Substitution of Some Oxides*

Abstract

These changes, which are brought about by variations in specific gravity and additions of electrolytes in the enamels studied, represent a wider range in set conditions than normally encountered in a laboratory or plant production work.Only those data pertaining to a typical commercial zirconia-opacified sheet-steel cover enamel have been presented since they embrace such a large span of consistencies. However, some exploratory studies have been made on other enamels such as a sheetsteel ground coat and a titania-opacified cover coat with highly satisfactory results. Sufficient data were obtained t o indicate the viscosimeter's successful application to these enamels.If handled with reasonable care and observing certain precautions, the Brookfield Svnchro-Lectric, or similar instrument, should afford the following advantages in measuring or controlling enamel slip consistency :(I) Rapid determinations.(2) Results translatable into absolute viscosity units.(3) Wide ranges.(4) (5) Portability.High accuracy and good reproducibility. CHICAGO VITREOUS ENAMEL PRODUCT COMPANY RESEARCH LABORATORIES CICBRO, ILLINOISABSTRACT Optical glasses with high indices of refraction and Abbe values are very desirable for wide angle lenses. In order to determine the range of compositions in which glasses of this type could be produced, oxides of lithium, beryllium, calcium, boron, lanthanum, or thorium were substituted for barium oxide or silica in a three-or-four component base lass. Substitutions were made on a mole-for-mole basis. The indices of refraction for glasses with indices of refraction ( n~) and Abbe values from 1.600 to 1.714 and 62.2 to 52.7, respectively, were made in small platinum crucibles.'i, t e C, D, F, and G' lines and the liquidus were determined for each glass. Experimental