Product Code: ICAL08_M404

Glass Strengthening with an Ultrafast Laser
Authors:
A. Streltsov, Corning Inc; Corning NY USA
J. Helfinstine, Corning Inc.; Corning NY USA
J. Price, Corning Inc.; Corning NY USA
J. Schroeder, Corning Inc.; Corning NY USA
J. Westbrook, Corning Inc.; Corning NY USA
N. Borrelli, Corning Inc.; Corning NY USA
Presented at ICALEO 2008

We performed experiments on laser strengthening on a number of glasses and glass-ceramics. The objective of this study was to identify the mechanism of strengthening and to establish the correlation between the residual stress and the apparent fracture-toughness increase. After the laser exposure, the stress was measured interpreting the resulting birefringence pattern (Polscope). The apparent fracture toughness was measured by a Double-Torsion method, which required a minimal number of samples to reliably detect the effect of laser treatment as compared with the four-point bending test. We discovered that the apparent fracture-toughness increase is proportional to the magnitude of laser induced stress. We also present the results on how the glass strengthening is influenced by the irradiation pattern and laser parameters.