MO_2-PO_<5/2>(M=Si,Ge)系ガラスのラマンスペクトル

概要

論文の詳細を見る
Raman spectra of MO_2-PO_<5/2> (M= Si, Ge) glasses were measured and their relative intensities were corrected. Two models were assumed for glass structure. In model 1. PO_3=O and MO_4 tetrahedra are randomly connected. In model 2, a part of M^<4 +> changes its coordination number from 4 to 6 with coordination of two oxygen atoms of P= O bonds. In model 2, the intensity of P= O stretching vibration depends on the amount of 6-coordinated M^<4 +>. The composition dependence of intensities of P=O stretching vibration proposed the following change in the glass structure. In GeO_2-PO_<5/2> glasses which have no P= O stretching vibration, 6-coordinated Ge^<4 +> is formed in model 2 and its content increases with increasing PO_02 content. The structure of SiO_2-PO_<5/2> glasses is described by model 1 and the coordination number of Si^<4 +> is 4 up to 20 mol% PO_<5/2> content. In the composition range containing more than 20 mol% PO_<5/2>, 6-coordinated Si^<4 +> is formed in model 2. The observed difference between these two glass systems is interpreted as follows. Six coordinated Ge^<4 +> can be formed if six tetrahedra connected to GeO_6 include at least two PO_4, whereas SiO_6 octahedron needs connection of PO_4 tetrahedra at many or all vertices.
社団法人日本セラミックス協会の論文
1988-03-01