Important factors in the weathering of commercial flint glass containers were determined by the storage of empty bottles, capped and uncapped, of ten different compositions for periods up to 3 months at (1) 100 deg F., 80% relative humidity; (2) 120 deg F., 15% relative humidity, and (3) normal room conditions. The effect of storage was determined by visual inspection, tests of the alkali extraction by water at elevated temperatures, and photomicrographs of the weathered surfaces. The results obtained indicated that the most important factor in the weathering conditions used is the humidity. Although the weathering produced depends on several factors, the important weathering effect of high humidity may be significantly controlled by the chemical composition of the glass. Storage for the periods used at low relative humidity or at normal room conditions was relatively innefective for weathering of any of the bottles tested. Photomicrographs of representative weathered internal and external bottle surfaces are shown. A microscopic examination of these surfaces revealed the presence of calcite.
