Determinations of structure and bonding in vitreous B2O3 by means of B10, B11, and O17 NMR

B¹⁰, B¹¹, and O¹⁷ NMR were used to study B₂O₃ glass. B¹⁰ NMR was employed to determine the most probable values and the Gaussian widths (σ) of the distributions of the quadrupole coupling constant (Q_cc) and the asymmetry parameter (η). The resulting values are Q⁰_cc=5.51 MHz, σ_Qcc=0.21 MHz, η⁰=0.12, and σ_η=0.043. These values are consistent with results using B¹¹ NMR. The O¹⁷ NMR spectra are obtained and analyzed using two sites: site 1 is characterized by Q⁰_cc=4.69 MHz, σ_Qcc=0.10 MHz, η⁰=0.58; site 2 is characterized by Q⁰_cc=5.75 MHz, η⁰=0.4, and σ_η=0.2. Only small distributions are present for site 1 and for Q_cc of site 2. A Townes-Daily calculation was employed, using the boroxol ring model of B₂O₃ glass, to determine the charge distributions and the B-O-B angle outside the boroxol rings. The results are consistent with a structure composed of randomly oriented boroxol rings.