Glasses synthesized on the basis of the R<sub>2</sub>O-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> system, where R<sub>2</sub>O is Na<sub>2</sub>O or K<sub>2</sub>O, have been investigated for the reflective and protective claddings of optical fiber. Laws have been established to describe how the oxides affect the glass-forming capability of optical glasses and their tendency to crystallize in the temperature interval in which optical fiber is drawn and to describe their thermal and optical characteristics. Laws have also been established to describe how the composition and structural factors affect the rheological properties of glasses for the claddings of optical fibers. The optimum concentrations of Al<sub>2</sub>O<sub>3</sub>, BaO, and MgO additives have been determined so that their introduction into the composition of the glasses for the light-reflecting cladding ensures that the temperature interval in which the viscosity of the glasses varies from 10<sup>9</sup> to 10<sup>4</sup> Pa sec is at least 360°C. The glasses for the light-reflecting and protective claddings are matched with the glass of the light-conducting core with respect to viscosity indices.
© 2014 Optical Society of AmericaPDF Article