Abstract :
[en] Spring, W. Recueil des Travaux Chimiques des Pays-Bas (1900), 19, 339-49; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010).
Ruby-glass is made by the addition of traces of gold chloride to an ordinary fused glass; the glass so obtained is at first colourless and only assumes a ruby colour during subsequent prolonged heating. When an intensely luminous electric beam is passed tangentially through a small cylinder of the colourless gold-glass, practically no internal illumination is visible; in the case of the ruby-glass, however, a yellowish-brown, luminous trace is produced, probably due to reflection from minute particles of metallic gold. The intensity of colour of the ruby-glass depends on the time of its reheating, and determines the intensity of illumination necessary to produce a visible trace; the deeper the colour of the glass the less illumination is required. In the colourless glass, the gold probably exists in a state of extreme subdivision, and the reheating which produces the ruby colour brings about a coarser colloidal aggregation, similar to that which takes place in gelatino-bromide plates during maturation (de Bruyn, Rec. Trav. Chim., 1900, 19, 236). Red glass coloured by copper, and yellow glass coloured by silver, show respectively dull brown and greyish luminous traces, due to the finely divided metals. Glasses coloured by silicates of iron, chromium, manganese, and cobalt show only a faint luminous trace, and, allowing for the presence of small air bubbles, are optically "void" (vide). Glasses which are colourless of themselves show a faint bluish trace and are yellow when viewed through a great length; they thus resemble media containing an extremely minute turbidity (compare Abstr., 1899, ii, 537, 585). Glass decolorised by manganese compounds shows an intensely green fluorescence, the luminous trace being green when the incident light is either violet or blue, but suppressed when it is green, yellow, or red. Glasses containing iron alone or manganese alone are not fluorescent.
Reprinted with the permission of the American Chemical Society. Copyright © 2010. American Chemical Society (ACS). All Rights Reserved.
