Stability in storage is a requisite of commercial glass. Weathering effects can be produced artificially by several methods which are given in this paper. Several factors, including humidity, have been found to influence the rate at which weathering takes place. Three classes of weathering effects are given and illustrated here. Experiments show that continued boiling removes the weathered surface. Weathering is largely dependent on solubility. Glass showing the greatest resistance to weathering proves equally resistant to action of water at temperatures and pressures above normal. The surface condition appears to influence its solubility. Alumina increases the resistance of glass to weathering. Sodium carbonate may exist in glass after manufacture and assist in the weathering process.
