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ON THE DETERMINATION OF THE CONSTITUTION OF GLASSES 1
Author(s) -
Tadata Kozo
Publication year - 1926
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1926.tb17962.x
Subject(s) - crystal (programming language) , silica glass , molecule , viscosity , mineralogy , chemistry , materials science , chemical physics , thermodynamics , physics , composite material , organic chemistry , computer science , programming language
This method of determination of the constituents of glasses is entirely new in its way. It is derived from the author's experiments on the causes of the surface devitrify‐cation of glasses. It is quite natural to produce crystals in glasses when heated several times at high temperatures. The glasses are super cooled liquids and are very viscous at low temperatures. But, when they are heated at higher temperatures, they attain low viscosities to produce crystals in them. In general, the chemical composition of the crystals produced (primary phase) in ordinary glasses without B 2 O 2 is SiO 2 . And for production of an elementary body of crystals of silica, there should be at least three neighboring molecules of silica moving within some ranges of speed. The motion of such molecules in glasses is set by two causes: the one is that quantity of energy given to the molecules by heating, and the other is that lowering of viscosity of the medium by heating. Heating glasses to certain temperatures is the exclusive cause of the crystal production of glasses. This has been already explained by many persons and no ambiguity has been left unsolved. The author has given another important cause for crystal production on glass surfaces and has described the interpretation. 3 From these views, the author has arbitrarily defined devitrify‐cation in five degrees. They are seen in accompanying photographs. It has been determined that these degrees of devitrify‐cation were entirely coincident with the quantities of dissolved silica in glasses. The experiments have been conducted for a series of glasses of alkali silicates and alkali lead silicates. From the results of these experiments, the author has determined the constitutions of those silicates in glasses to be meta‐disilicates and the double compounds to consist of those meta‐disilicates. As the result of the determination of the constituents of alkali silicates and of alkali lead silicate glasses, it is pointed out that the compositions of crucibles to melt glasses of different silica content, should be either rich Al 2 O 3 : or rich SiO 2 according to the dissolving power of glasses for silica.