Na_2O-B_2O_3系ガラスの平均配位数とフラジリティーの関係

概要

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Viscosities and thermal properties of glasses in the Na_2O-B_2O_3 system were investigated in the temperature region of glass transformation. The values of ΔC_p and Eη/T_g, where ΔC_p is the heat capacity change during glass transition and Eη is the activation energy for viscous flow at around the glass transition temperature T_g, were maximum at 30 mol% Na_2O, indicating that the fragility of liquid was maximized at the composition where the BO_4 tetrahedral unit was maximum in the corresponding glass. The relationship between the measures of liquid fragility and the average coordination number<γ>of the elements comprising the glasses was discussed on the basis of Phillips'idea concerning the degree of bond constraint and glass-forming ability.
社団法人日本セラミックス協会の論文
1995-04-01