NMR and NQR Studies of Borate Glasses

Abstract

Nuclear magnetic resonance (NMR) has been used for some 40 years to study atomic arrangements, chemical bonding, and structural groupings in borate glasses and crystalline compounds, and nuclear quadrupole resonance (NQR) has more recently increased the resolution and accuracy of the measurements. Examples are presented of the use of first-order and second-order quadrupolar effects in "B NMR spectra to obtain structural information, and n B and 10 B NQR spectra to obtain the quadrupolar parameters Q cc (the coupling constant) and 77 (the asymmetry parameter) with accuracies of 5 or 6 significant figures, and 3 figures, respectively. Q cc and 77 are extremely sensitive to changes in atomic rearrangements and chemical bonds, so they are excellent monitors and provide identification of bonding configurations and structural groupings in borates: Examples are also presented in which combinations of NMR and NQR data are used to extract the desired information. NQR detection of resonances at frequencies as low as 276 kHz is discussed.

Network connectivity in cesium borosilicate glasses: 17O multiple-quantum MAS and double-resonance NMR

“…The use of solid-state nuclear magnetic resonance (NMR) for studying borate glasses dates back many decades [9][10][11][12]. 11 B NMR was one of the early spectroscopic techniques to make an impact on determining the short-range structure of glasses [12].…”