Effect of 3B Group in Rings on Special Dispersion of B2O3-SiO2-ZrO2-Ta2O5-Na2O System Glass

Borosilicate glasses, with x B 2 O 3 -(60- x )SiO 2 -8ZrO 2 -8Ta 2 O 5 -24Na 2 O (7≤ x ≤59 mol%) composition, were fabricated by melt-quenching technique. NMR, UV-Vis, Raman and IR spectroscopic studies were utilized to investigate the structure of fabricated glasses. The NMR spectrum was deconvoluted into five Gaussian bands, assigned to 4 B(0B,4Si), 4 B(1B,3Si), 4 B(2B,2Si), 3 B(rings) and 3 B(loose), to get their quantitative information. The relative dispersion deviation Δ P g , F was attributed to the relative quantity of 3 B (rings) but not all 3 B groups, and B 2 O 3 existed mainly as [BO 3 ] in rings firstly, and then as [BO 3 ] in loose condition. The UV-Vis spectra revealed that the quantity of non-bridging oxygen increased firstly and then decreased with increasing concentration of B 2 O 3 . Acting as complementary techniques, Raman and IR measurements revealed that four-coordinated boron and silica mainly existed as 4 B-O-B, and Si-O-Si in Q 2 , respectively, as chain structure but not framework structure, and [BØ 4 ] units prefered connections with borate rather than with silicate entities of the glass network in these studied glasses. In addition, the conclusion also certified that 3 B in “loose” condition located in lower wavenumbers between 1 200 -1 600 cm-1 in Raman spectra.