TIME-RESOLVED FRACTOLUMINESCENCE SPECTRA OF SILICA GLASS IN A VACUUM AND NITROGEN ATMOSPHERE

Time-resolved fractoluminescence spectra of silica glass are investigated at room temperature in a vacuum and nitrogen atmosphere. Two emission bands are seen in the spectra: the 1.9- and 2.7-eV bands. The 1.9-eV band peaks around 5 mu s, and decays around 100 mu s after the instant of fracture. The 2.7-eV band rises in about 50 mu s, peaks around 500 mu s, and decays in several tens of milliseconds after fracture. The energy position and the time response of the two bands are similar to those in the photoluminescence of silica glass. The role of the surface defect centers to the fractoluminescence of silica glass is discussed.