The presence of interstitial oxygen molecules in glassy ${\mathrm{SiO}}_{2}$ has been demonstrated directly by 1064.1 nm $({\ensuremath{\nu}}^{\ensuremath{'}\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0)\ensuremath{\rightarrow}({\ensuremath{\nu}}^{\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1)$ excitation of the forbidden ${O}_{2}$ molecule $^{1}\ensuremath{\Delta}_{g}({\ensuremath{\nu}}^{\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0)\ensuremath{\rightarrow}^{3}\ensuremath{\Sigma}_{g}({\ensuremath{\nu}}^{\ensuremath{'}\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0)$ luminescence transition at 1272 nm in Suprasil W1 fused silica. The interstitial ${\mathrm{O}}_{2}$ molecules, introduced into glass network during the synthesis process, are destroyed by vacuum ultraviolet or neutron irradiation. Mobile O atoms may play an important role in radiation processes in ${\mathrm{SiO}}_{2}$. The directly photoexcited luminescence of ${\mathrm{O}}_{2}$ could be used to detect the presence of ${O}_{2}$ in other solid state matrices as well.