Cladding glasses for photochromic optical fibers

Abstract

Abstract This invention relates to the discovery of glass compositions suitable for cladding photochromic optical fibers. Such glasses consist essentially, in weight percent on the oxide basis as calculated from the batch, of about 50-67 percent SiO2, 5-15 percent Al2O3, 5-25 percent B2O3, 0-5 percent P2O5, 0-5 percent RO wherein RO is one or more oxides selected from the group consisting of CaO, SrO, MgO, ZnO, BaO and NiO, 0-5 percent Li2O, 0-12 percent Na2O, 0-10 percent K2O and 0-5 percent Cs2O, wherein (2Li2O + Na2O + K2O + 1/2Cs2O) is at least about 10 percent, 0-10 percent TiO2 and 0-10 percent CeO2, wherein (TiO2 + CeO2) does not exceed about 10 percent, 0-0.5 percent Sb2O3 and 0-0.5 percent As2O3, to which may be added 0-15 percent F, as calculated in excess of the weight of the other glass constituents. These glasses are particularly useful because, in addition to combining proper thermal expansion and refractive index with good ultraviolet light absorption, they do not deleteriously effect the natural fading rate of the photochromic core glass during the fabrication of the cladded fiber optic.

Inventors

• 👤 R Araujo
• 👤 L Sawchuk

Bibliographic Details