Abstract
Magic-angle spinning nuclear magnetic resonance measurements have been performed on nuclei in amorphous silica before and after densification ∼16% by pressure compaction at 50 kbar and 600?deC. The pressure-induced shift in the Si—O—Si bond-angle distribution maximum from 143° to 138° is consistent with results obtained from x-ray scattering and Raman spectroscopy. Variation in the bond-angle distribution is discussed in terms of recent models for the structure of amorphous . It is concluded that the important parameter modified by densification is the oxygen–second-nearest-neighbor-oxygen smallest distance of approach. This in turn leads to a variation in the nature of the short-range order.
- Received 8 October 1986
DOI:https://doi.org/10.1103/PhysRevB.35.2560
©1987 American Physical Society