Fundamental defect centers in glass : The peroxy radical in irradiated high-purity fused silica

A new fundamental radiation-induced defect in high-purity synthetic silica has been identified by electron-spin-resonance studies of $^{17}\mathrm{O}$-enriched Si${\mathrm{O}}_{2}$ as a peroxy radical ${\mathrm{O}}_{2}^{\ensuremath{-}}$ bonded to one Si in the glass matrix. The precursors of these defects are envisioned to be \ensuremath{\equiv} Si-O-O-Si \ensuremath{\equiv} structures, some of which preexist in the silica, are formed in greater numbers during neutron bombardment, and which may release an electron either during irradiation or subsequent annealing.