Colour Centres in Metaphosphate Glass

Abstract

IN a recent communication¹, Basu states that we have attributed the coloration of metaphosphate glasses, induced by X-rays, to the activating influence of the metal (aluminium, barium, silver, etc.) in the glass, and that his results with sodium metaphosphate glasses show that ‘F-centres’ can be produced without these activators. In the references to our work cited by Basu^2,3, the point is made that radiophotoluminescent centres having certain specific properties are connected with the presence of silver in potassium–barium–aluminium metaphosphate glass. It is clearly shown, we believe, in the publications from this Laboratory^3–5 that a visible coloration is produced upon X-irradiation of the above silver-free base glass, two broad bands appearing with peaks at about 420 mµ and 530 mµ. These colour centres were not attributed to any ‘activating’ influence of the aluminium, barium or other metallic constituents of the glass.