VARIATIONS OF REFRACTIVE INDEX OF GLASS WITH TIME AND TEMPERATURE IN ANNEALING REGION *McMaster, Harold A.
doi: 10.1111/j.1151-2916.1945.tb14483.xpmid: N/A
Abstract The refractive index of a rapidly cooled fiber of borosilicate glass was found to increase according to the equation, 1/(N6–N) – 1/(N6–N0) =At, where t is time, N6 is equilibrium index, and A is a constant at constant temperature. Index data were plotted according to this equation to determine, graphically, values of N6 and A for several temperatures between 914° and 1060°F. Values of N6 for temperatures from 1060° to 1180°F. were determined by prolonged heating of the glass at each 20° interval. The change of A with temperature was found to be well represented by the equation, log A=K/T+C, where T is the absolute temperature and K and C are constants.
SOFTENING POINT OF GLASS BY FIBER ELONGATION METHOD AND IMPROVEMENTS IN APPARATUS AND PROCEDURE *Falter, Arthur H.
doi: 10.1111/j.1151-2916.1945.tb14484.xpmid: N/A
Abstract Detail and assembly illustrations show how the apparatus has been redesigned to maintain a constant rate of heat transmission. A description of the comparator telescope and the method of use is given. Individual curves show the results of softening‐point tests on glasses over a range of 260°C., in which the agreement for five individual homogeneous glass specimens varies from 1° to 6°C. when the ordinary portable potentiometer is used. When the glass contains stones or is devitrified, the results are more widely divergent. Uniformity of specimen diameter has a slight effect on the results.
LEWIS ACID‐BASE THEORY APPLIED TO GLASS *Sun, Kuan‐Han; Silverman, Alexander
doi: 10.1111/j.1151-2916.1945.tb14485.xpmid: N/A
Abstract According to the Lewis theory of acids and bases, glass formers, such as SiO2, B2O3, P2O5, BeF2, GeS2, etc., may be classified as acids because they are electron‐pair acceptors in glass reactions and the modifiers, Na2O, CaO, NaF, Na2S, etc., are bases because they are electron‐pair donors; Al2O3, Fe2O3, BeO, MgO, ZnO, etc., the intermediates, may be classified as amphoteric.
QUALITATIVE SPOT TESTS FOR COMMON CONSTITUENTS IN GLASS *Zerfoss, S.; Hess, R. L.
doi: 10.1111/j.1151-2916.1945.tb14487.xpmid: N/A
Abstract A procedure is outlined for routine qualitative analysis of certain common constituents of glass by means of spot tests using organic reagents according to the technique of Feigl. Sampling of the glass has been accomplished previously by using the powdered glass or by attacking the glass surface. A technique is discussed for the nondestructive testing of fabricated samples. Using this technique, a sample may be obtained by scratching the glass against a quartz plate. The method shows promise as a practical laboratory and plant tool.
CLASSIFICATION OF NATURAL ORGANIC BINDERS *McNamara, Edward P.; Comeforo, Jay E.
doi: 10.1111/j.1151-2916.1945.tb14489.xpmid: N/A
Abstract Modulus of rupture, loss on tumbling, migration, water absorption, and burn‐out characteristics were studied using a series of organic compounds representative of the types used as binders for ceramic materials. The results are interpreted in terms of the constitution of the organic compounds and in terms of the mechanism of specific adhesion. The binding strength of an organic material may be predicted from a knowledge of its molecular constitution.
DETERIORATION OF GLASS IN TROPICAL USE *Jones, Frank L.
doi: 10.1111/j.1151-2916.1945.tb14490.xpmid: N/A
Abstract Glass deteriorates rapidly in tropical regions with a high relative humidity. Transparency decreases due to the growth of deposits of corrosion products, chemical decomposition of the surface layer to produce pits or holes, or contamination of the surface by organic material. The processes involved in tropical deterioration are similar to the chemical reactions of glass and water in other environments.