Nippon Sheet Glass Company, Limited

Yoshirou Ikeda

Yoshikazu Kaite

Toshiro Ikuma

This invention provides a light-transmitting glass having superior weatherability which has the following composition in % by weight:

Optical glass fiber having cover glass of sodium zinc alumino

A step-type light-transmitting body having excellent water resistance, said light-transmitting body comprising a core material of a glass having the following composition in % by weight: (1) SiO.sub.2 15-40, (2) ZrO.sub.2 8-17, (3) B.sub.2 O.sub.3 5-15, (4) BaO 30-45, (5) Na.sub.2 O 3-15, as essential ingredients, and (6) GeO.sub.2 0-30, TiO.sub.2 0-3, Al.sub.2 O.sub.3 0-5, La.sub.2 O.sub.3 0-5, MgO 0-5, CaO 0-7, ZnO 0-7, SrO 0-5, Li.sub.2 O 0-8, K.sub.2 O 0-10, Rb.sub.2 O 0-5, and Cs.sub.2 O 0-8, as additional ingredients; provided that SiO.sub.2 +GeO.sub.2 15-50, ZrO.sub.2 +BaO 38-55, Na.sub.2 O+Li.sub.2 O+K.sub.2 O+Rb.sub.2 O+Cs.sub.2 O 5-15, and MgO+CaO+ZnO+SrO+TiO.sub.2 +Al.sub.2 O.sub.3 +La.sub.2 O.sub.3 0-12. In the above composition, the amounts of (2) ZrO.sub.2, (3) B.sub.2 O.sub.3, (5) Na.sub.2 O and ZrO.sub.2 + BaO may be changed to 8-15, 7-12, 5-12, and 38-50, respectively.

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Nishinomiya, Japan

Yoshirou Ikeda