The Structure and Constitution of Glass

JSGT_1927_V11_T077_T097

The problem of the structure and constitution of glass has received a large amount of attention during the past fifty years, whilst quite recently our knowledge of the subject has been summarised in a symposium published in the Journal of the Society of Glass Technology. Careful study of that symposium, however, and of a number of other papers, leaves the reader with the impression that, beyond an elementary, but none the less fundamental generalisation, our knowledge is still vague. That fundamental generalisation is that glass must be regarded as an amorphous solid or under-cooled liquid, and although this view is more fully established to-day, it has been used by the author for purposes of discussion and research for more than 25 years. The problem, however, is thereby shifted rather than solved, since we are left with the wider problem as to the real nature and structure of under-cooled liquids or quasi-solid amorphous substances. Such a widening of the subject is further rendered necessary by the recent work of Le Chatelier and of Samsoen who have shown that certain phenomena believed to be typical of glass are met with in amorphous substances generally. This widening of the problem, however, implies also a certain narrowing of the range of investigation and of speculation, since the specific problem of the chemical constitution of glass loses much of its wider importance once it is recognised that, whatever its proximate chemical constitution, glass behaves much as any other super-cooled liquid of complex composition. It is, however, suggested below that the physical structure and proximate chemical constitution of such bodies are inter-related in a special manner.

Walter Rosenhain