<sup>29</sup>Si MAS NMR Study of Porous Silica Glass Prepared from Sodium Borosilicate Glasses

Abstract

Porous silica glass was prepared by phase separation of sodium borosilicate glass. The distributions of SiO4 structural units, Qn, were examined by 29Si magic-angle spinning (MAS) NMR after each process in a series of acid and thermal treatments. The NMR spectra reveal three distinct peaks due to the presence of a silanol group on the surface of the porous silica glass. However, only a single peak around -110ppm that originated from a Q4 unit which lacked any OH groups could be observed after heat treatment at 900°C.