On The Origin Of Flaw Development On Normal Glass Surfaces (In German)

The presence of flaws on ordinary glass surfaces can be explained by assuming that the most weakly bound cations are enriched in the surface and swarm together to achieve better co-ordination. These swarms produce - because of their greater coefficient of expansion that the surroundings - tensile stresses causing flaws even at lower strain. The high strength of etched glass fibres results from the elimination of these swarms. Heat treatment of fibres decreased their tensile strength because the swarms can form again.