Boroaluminasilicateglass

Boroaluminosilicate glass containing (wt.%) : SiO 2(35-50), B 2O 3(0.1-7), Al 2O 3(0.1-7), P 2O 5(0.1-4), R 2O (4-24), RO (0-12), BaO (6-14.5), ZnO (14-25), La 2O 3(0-5), ZrO 2(0-10), where R 2O = alkali oxide, RO = alkali earth oxide, except BaO, the maximum amount of Li 2O = 6 wt.%, and the glass, except for chance impurities, contains no GeO 2, SnO, SnO 2, or Sb 2O 3, AgO and no rare earths, with addition of preferably up to 1 wt.% pure agents. Independent claims are included for : (a) a glass in which the pure agent is selected from at least one group formed from Sb 2O 3, As 2O 3, SO, NaCl, SO 42>-, and F ->, and is added in amount up to 1 wt.% on the melt; an optical fiber from multicomponent glasses with a core glass as above with a sheath glass (sic) at its peripheral and having a numerical aperture size of 0.28-.70.