OH-content dependence of fractoluminescence spectra in silica glass

The effect of OH content on fractoluminescence spectra in silica glasses was investigated. The spectra consisted of the 1.9- and 2.7-eV bands. The intensity of the 2.7-eV band was larger in lower OH samples. This is because the oxygen-deficient center (ODC) can be more easily created on the fracture surface of silica glasses with lower OH content. Moreover, silica glasses containing little OH have preexisting ODC's, and they are excited by fracture to emit the 2.7-eV photons. The origin of the preexisting ODC's and the ODC formation mechanism at fracture of silica glasses are discussed. {} 1996 The American Physical Society.