Experimental Method for Developing Minute Flaw Patterns in Glass

Abstract

A new chemical etching technique was used to study minute flaw patterns in glass. The etched structure disclosed that the minute defects react to the chemical treatment in a different manner than ordinary fissures. Flaw patterns formed at the tips of slow‐moving internal cracks were analogous to dislocation phenomena in crystals. Oriented and repeating flaw groupings were observed in various types of glass. These patterns are produced above the ``strain point'' and were shown to be influenced by permanently induced stresses and internal homogeneity. Fracturing by localized stresses created flaw patterns radiating from the point of origin with shapes similar in appearance to shock wave phenomena. The impact breaking strength of glass containers was directly influenced by the number of flaws. The flaw distribution decreased rapidly with decreasing diameter of glass fibers.