Glasses, Organic and Inorganic

JSGT 1939 V23 T347-T371

Two years ago, or even less, I should have objected strongly to giving a lecture with this title, because I dislike the term "organic glass" I still consider it unfortunate that the word "glass" should be used as a general description for all types of amorphous solids or pseudo-solids, instead of being restricted to solid nanocrystalline inorganic materials. In view of the almost universal acceptance of this meaning nowadays, however, I must content myself with merely recording a protest and fall into line. I remember the term "flexible glass" being used to describe celluloid when it was introduced during my early youth, but the term "organic glass" does not appear to have come prominently into use until about 1924, when it was used to describe "Pollopas", the urea-formaldehyde resin developed by Pollak, which attracted so much attention about that time. The possibilities of this new material as a substitute for glass in particular applications were perhaps somewhat over-rated, partly as a result of the claims made by its inventor, and partly owing to imaginative articles contributed to both technical and non-technical sections of the press. They could not be entirely disregarded by the glass interests, and in 1926 a useful survey of the position from the "glass angle" was made in the Glass Review under the title "Substitutes for Glass and a Newly Advertised Invention." The survey was not confined to a consideration of the properties of Pollopas as compared with glass, but was extended to include mica, rock crystal, cellulose nitrate, and cellulose acetate. At that time there was not much direct evidence of the nature of glass, nor was the nature of the "organic glasses" entirely established; nevertheless the indirect evidence was considerable, and the author of the article was bold enough to draw a parallel between cellulose and silica glass, describing both materials as complexes of simple molecules "clotted" together.

Harry Moore, D.Sc.