Compressive surface stresses in glass: An old curiosity?

Residual stresses in glass have moved from a curious fascination to a usefu l and successful industrial technology. In some cases, however, these stren gthening processes for glass can lead to increases in strength variability. A new approach has been established that allows residual stresses to be in troduced into a brittle material that increase strength and decrease streng th variability. These stress profiles lead to crack growth stabilisation, c rack arrest and multiple cracking prior to failure. It is suggested these i deas need to be extended to other glasses and to other types of materials a nd structures; allowing the curiosity to continue into the new millennium.