Gases in Glass. Part II. The Gas and Moisture Content of Glasses
JSGT 1929 V13 T098-T111
It is obvious that the large quantities of gases evolved during the melting down of the batch are produced by the decomposition of the individual constituents of the batch, e.g,CO2, SO2, and O2, from carbonates, sulphates, and the higher oxides. It is debatable, on the other hand, whether the fine bubbles which appear during the refining of glass or when cold glass is remelted, are due to gas dissolved in the chemical or in physical slate. It is possible to conceive of the solution of these gases in a glass in a physical manner similar to the solution of gases in liquids. A chemical solution may be conceived by imagining the gases to be present in the form of compounds, such as carbonates, sulphates, and oxides, which have escaped destruction during the melting process. The evolution of these gases during remelting may then be conceived to be a kind of secondary refining. The decision as to which point of view, the physical or the chemical, is correct, however, must be settled by experiment.
A. Becker & H. Salmang (Translated by H. W. Howes)