Cladding glass for optical fiber

摘要

A cladding glass for optical fiber comprises 60 to 80% by weight of silicon dioxide (SiO2), 0.5 to 10% by weight of aluminum oxide (Al2O3), 9 to 17% by weight of an alkali metal oxide, 3 to 15% by weight of boron oxide (B2O3) and more than 0 but not more than 3% by weight of fluorine (F). The cladding glass of this invention can simultaneously satisfy low refractive index and lowered viscosity, and is also excellent in water resistance and weathering resistance.