2D PASS-CPMG: A New NMR Method for Quantifying Structure in Non-Crystalline Solids

Quantifying the distribution of Q⁽ⁿ⁾ species in silicate glasses has been of particular interest to researchers interested in the structure of silicate glasses. Previously,²⁹Si MAS NMR experiments have been used to quantify the Q(n) species assuming that the overlapping isotropic chemical shift distribution of Q⁽ⁿ⁾ species is Gaussian. However, due to strong overlap of the Q⁽ⁿ⁾ resonances this technique has considerable uncertainty. In this thesis we introduce 2D PASS-CPMG, a new method for the quantification of Q⁽ⁿ⁾ species. In this method we obtain a correlation between the spinning sidebands and the fast spinning MAS spectrum. By adding CPMG to the 2D PASS we are able to increase the sensitivity and investigate inexpensive, unenriched ²⁹Si samples.

In the first chapter of this thesis, the importance of glasses and a brief overview on the structure of glasses is discussed. Next, a few of the previous studies that have been done and the previous methodologies used in quantifying the Q⁽ⁿ⁾ species are also discussed. In chapter two, the new 2D PASS-CPMG experiment is discussed. Experimental data on a silicate glass with the composition of 2Na2 O·3SiO2 is pre- sented.