| 摘要 |
PROBLEM TO BE SOLVED: To obtain glass capable of being processed into one or more fibers in a sufficient amount by adding a valency-changeable element and a valency- controlling substance to glass raw materials and subsequently thermally melting the mixture into the glass in a non-reducing crucible under a non-reducing atmosphere. SOLUTION: This glass is obtained by charging glass raw materials into a non-reducing crucible 1 comprising alumina, further charging a valency- changeable element such as Sm and a valency-controlling substance such as carbon preferably in amounts of <=5 mol.% and <=0.5 wt.%, respectively, homogeneously mixing the mixture, setting the crucible 1 to the inside of a heating oven 3, charging N2 gas, etc., from a non-reducing gas-charging pipe 5 into the heating oven 3, and simultaneously heating the raw material mixture up to a prescribed temperature to produce the melted glass. In the processes, the valency-changeable element is reduced (3-valency element→2-valent element). The obtained glass can stably express a photochemical hole burning(PHB) phenomenon at the ordinary temperature. |
