Environmentally Enhanced Crack Growth in Soda‐Lime Glass

Crack growth data are presented for soda‐lime glass in various chemical environments. It is shown that the same environments which govern crack growth rates in vitreous silica also do so in soda‐lime glass. The slopes and positions of the crack growth curves in soda‐lime glass are shown to differ from those in vitreous silica. It is hypothesized that the differences between the behavior of soda‐lime glass and silica result from the effects of the modifier ions, Na + and Ca 2+ , on the reactivity of the Si‐O bond or through changes in the elastic properties of the bridging network. It is shown that sodium ion exchange and silica dissolution may also be important to crack growth, particularly at low crack velocities.