Nuclear Magnetic Resonance Studies of Atomic Motion in Lithium Chloroborate and Lithium Thiosilicate Glassy Fast Ionic Conductors [Thesis]

The NMR spectra and T₁ measurements on both the stationary ¹¹B in the lithium chloroborate glass and on the mobile ⁷Li in both the lithium chloroborate and lithium thiosilicate glasses have yielded much useful information about the static and dynamic properties of these two glassy fast ionic conductors. The ¹¹B spectra for the B₂O₃ + 0.7Li₂O + XLiCl glasses indicates that the boron nuclei sit in two different sites. The narrow central line is due to the ¹¹B nuclei that are in the BO₄ sites where there is no EFG and therefore no electric quadrupole effects and no splitting of the line. The broader pattern consisting of the two side peaks is a result of the ¹¹B nuclei that sit in the BO₃ sites. In these sites, the magnitude of the EFG tenser is large and second order splitting of the central transition is seen. These side peaks are smaller since they are due to essentially the same number of boron nuclei but the pattern is spread over a much larger range of frequencies. If a baseline for these spectra could be determined, the ratio of BO₃ to BO₄ could then be found. Nuclear spin lattice relaxation measurements of the ¹¹B nuclei show no dependence on the measuring frequency. Because of this, the theory proposed by Rubinstein and Resing which uses an adaptation of the Van Kronendonk theory and uses a two phonon Raman process for the relaxation is favored. Spin lattice relaxation measurements of the ⁷Li nuclei do show the frequency dependence that one expects from the nuclei that are free to diffuse through the glass matrix. 29 figs., 9 tabs.