Structure of Vitreous Silica

Abstract

OUR attention has recently been directed to a letter from S. S. Lu and Y. L. Chang¹ concerning the structure of vitreous silica. Two main claims are made. First, that the X-ray diffraction pattern of a thin plate of vitreous silica differs from that of the powdered material and consequently there must be some rearrangement of structure on powdering. Secondly, that the relative intensities of two strong bands in the pinhole transmission photographs of the thin plate vary according to the location of the specimen and that this indicates that large fluctuations occur in the structure of vitreous silica. Since, if true, these results would appear to suggest that the random network theory developed by Warren² is based upon incomplete experimental data, the experiments and conclusions described in the letter are worth critical examination.