NaF-Na₂O-B₂O₃系ガラスの高温ラマンスペクトル

抄録

Raman spectra of NaF-Na₂O-B₂O₃ glasses with B₂O₃ content=65, 80 and 85mol% were measured from ambient to 800°C. T_g and T_d of the glasses were measured. The results are summarized as follows.
(1) The Raman spectra of glasses in the NaF-B₂O₃ system are similar to those in the Na₂O-B₂O₃ system. The line width and the peak intenisity ratio of 770cm^-1 to 806cm^-1, I₇₇₀/I₈₀₆, are almost same in both systems.
(2) The peak positions of the Raman spectra shift toward lower frequency as temperature increases.
(3) The line width increases as temperature increases.
(4) The peak intensity ratio of 770cm^-1 to 806cm^-1, I₇₇₀/I₈₀₆, increases slightly with increasing temperature.
(5) T_g and T_d decrease as the NaF content increases.
From the above mentioned results it is inferred that the similar structural units are present both in the NaF-B₂O₃ and the Na₂O-B₂O₃ systems, and these structural units are mostly maintained at elevated temperatures. However, some structural rearrangement is implied above T_g among the borate groups containing four-fold coordinated boron atoms. The differences in T_g and T_d between the two systems are attributed to the fluoline atoms connecting the borate groups.