Multinuclear MAS NMR study of structural changes in LaF3 doped borosilicate glasses for optoelectronics

作者：Sroda Marcin^*; Olejniczak Zbigniew

来源：Optica Applicata, 2008, 38(1): 259-266.

• oxyfluoride glass
• borosilicate glass
• glass structure
• MAS NMR
• LaF3

A new type of oxyfluoride glass-ceramics based on the silicate glassy matrix and the nano-phase of LaF3 was developed for generating the up-conversion luminescence processes. In such material, the low-phonon energy crystals of LaF3 are desirable host for the rare-earth elements. The effect of admixture of 3 mol% of La2F6 on the structural changes of glasses in the Na2O-B2O3-SiO2 system was investigated. The effect of LaF3 additive was studied using Si-29, B-11, and Na-23 MAS NMR to learn more about the structural role of modifiers as well as fluorine in the glassy matrix. Glasses with compositions corresponding to different B2O3/Na2O and B2O3/(Na2O + 3La(2)F(6)) ratios in the 0.6-1.2 range were obtained by melt quenching. The Si-29 MAS NMR spectra indicated that the [SiO4] units are more polymerized when the ratios and the fluorine admixture increase. The B-11 NMR spectra revealed the presence of both [BO4] (Q(4)) and [BO3] (Q(3)) units. The fraction of Q(3) increased with the decreasing sodium content. Glasses with the LaF3 additive showed higher BO3/BO4 ratios. The effect of thermal treatment for glasses with the tendency towards LaF3 crystallization was discussed in terms of structural changes.

• 出版日期2008