Hydroxyl groups in high-purity silica glass

IR absorption spectra of high-purity silica glass (SiO2) of different types containing from 0.1 to 103 ppm of hydroxyl (OH) groups were studied and quantum-chemical calculations of different OH structures in the silica glass network were performed. On their basis a new approach to the problem of OH groups embedded in the glass network was proposed. It was shown that OH groups in high-purity SiO2 occur mainly singly rather than as paired groups. Some of them are linked by hydrogen bonds to bridging oxygen atoms and not to each other, as is considered now. A new decomposition of the fundamental OH-stretching vibrational band into components was proposed.