Boron phosphate glass with improved devitrification resistance, a method for its preparation and its use

摘要

1395942 Phosphate glass IMPERIAL CHEMICAL INDUSTRIES Ltd 9 April 1973 [27 April 1972 16 Aug 1972] 19560/72 and 38141/72 Heading C1M An inorganic oxide glass comprises, in mole percent: 1À2-3À5 B 2 O 3 ;50-72 P 2 O 5 ; 0-30PbO; 0-5 one or more transition metal oxides, and at least 3À5 mole per cent of oxides selected from alkali metal oxides, alkaline earth metal oxides and zinc oxide, the glass comprising at least one alkali metal oxide and at least one oxide selected from alkaline earth metal oxides and zinc oxide, the aforementioned oxides forming at least 99 mole per cent of the glass. Water (which is not considered for the above percentages) may be present in the glass in amounts up to 5% by weight. The transition metal oxide may be WO 3 . The glass, which preferably has a transformation temperature below 300‹ C., may be prepared by heating the oxides or their precursors at 500-800‹ C., after an optional pre-heating at 300-500‹ C. The glass may be formed into fibres or optical articles (e.g. lenses).