ラマン散乱スペクトルと化学平衡に基づくNa₂O-B₂O₃-GeO₂系ガラスの構造と物性

抄録

Ota and co-workers determined a set of equilibrium constants which govern the number density of the structural units in alkali borate glass. Based on the results, the molar volume of the system was computed. However, this technique can not be applied to the Na₂O-B₂O₃-GeO₂ system where the state analyses on Ge ions in the Na₂O-B₂O₃-GeO₂ system have not been fully conducted. In the present study a new method to calculate the molar volume of multi-component alkali borate system is presented. Raman spectra were used to elucidate that Na₂O affinity for B₂O₃ is stronger than that for GeO₂. Assuming the relative magnitude of activity coefficient γ of Na₂O for B₂O₃ against for GeO₂ tentatively 1:2, the distribution of Na₂O among B₂O₃ and GeO₂ was determined. The molar volume of the Na₂O-B₂O₃-GeO₂ system was calculated from the partial molar volumes of the sub-systems Na₂O-B₂O₃ and Na₂O-GeO₂ in good agreement with the experimental value.