ゾル-ゲル法で作製されたナトリウムゲルマン酸塩ガラスの構造 : 溶融法で作製されたガラスとの比較

概要

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(1) Sodium germanate glass of the mominal composition of 20Na_2O・80GeO_2 in mol% (analyzed composition of 21.8Na_2O・78.2GeO_2), which was particulate and some what porous, was made by heating the gel obtained from Ge(O・C_4H_9^n)_4 and NaOCH_3 by the sol-gel method. (2) The fraction of 6-fold coordinated Ge^<4+> ions in the sol-gel-derived glass, which was evaluated on the basis of X-ray radial distribution analysis, was about 40%, much larger than in the melt-derived glass (N_6=25%). The IR absorption data was consistent with X-ray data. (3) In the sol-gel-derived glass, major crystalline species precipitated on heating was Na_4Ge_9O_<20> in the melt-derived glass. (4) The large N_6 and crystallization behavior of the sol-gel-derived glass was interpreted in terms of the glass network consisting of edge-shared GeO_6 octahedra linked to GeO_4 tetrahedra, while melt-derived glass is made up by GeO_6 octahedra linked to GeO_4 tetrahedra at all six corners.
1993-11-01