A gas probe analysis of structure in bulk and surface layers of vitreous silica

Abstract

Analysis of relevant gas transport data indicates that interstices large enough to accomodate large atoms or molecules (e.g. Ar and O 2) are relatively isolated in the random network structure. Two dimensional schematics of the random network structure help to visualize this. The implication is that a “defect path” between large interstices is necessary. Possibilities in decreasing order of likelihood include: (i) channels, i.e. preferentially adjacent large interstices; (ii) local network reforming or dilation; (iii) mobile point defects; and (iv) dislocations.