Nuclear Magnetic Resonance Absorption in Glass. I. Nuclear Quadrupole Effects in Boron Oxide, Soda-Boric Oxide, and Borosilicate Glasses

Abstract

The nuclear magnetic resonance spectrum of B¹¹ has been investigated in several glassy materials containing boron oxide. A value of 2.76±0.05 Mc for the nuclear quadrupole coupling constant of B¹¹ has been calculated from the second‐order quadrupole perturbation of the m = ½→—½ resonance line. The same quadrupole interaction has been observed in pure boron oxide, B₂O₃, soda‐boric oxide binary glasses, and two commercial borosilicate glasses. The quadrupole coupling constant is interpreted as arising from the bonding electrons in BO₃ groups which comprise the glass network in boron oxide. Addition of oxygen ions to the glass network induces a change in the boron configuration from BO₃ planar groups to BO₄ tetrahedra resulting in a reduction in the quadrupole interaction. This effect has been observed in the Na₂O–B₂O₃ glasses and in Corning ``Pyrex'' and 707 borosilicate glasses.