Changes in the Tensile Strength of Glass Caused by Water Immersion Treatment

Abstract

An investigation was undertaken to determine quantitatively the effect of water immersion on the tensile strength of three commercial glasses. Test specimens were prepared by drawing sodalime, lead, and borosilicate glass rods down to constricted sections 0.011 to 0.012 in. in diameter. Substantial quantities of these carefully prepared constricted rods were broken in air and under water after varying periods of treatment in distilled water at 90°C. Breaking strengths of the test specimens are compared with strengths obtained on control specimens stored in a desiccator during the test periods. This comparative technique furnishes the most valid basis for comparison of results because the effects of any systematic errors in specimen preparation are minimized. Strength decreases of about 12% were found when freshly prepared specimens were broken under water. Extended water soaking treatments at 90°C. gave strength increases greater than 100% for the borosilicate glass. Interpretations of these results are discussed on the basis of the flaw theory of the weakness of glass.