Distribution of principal values of the 31P NMR chemical shift tensor in phosphate glasses.

The static line shapes of the powder pattern of the 31P nuclear magnetic resonance (NMR) chemical shift (CS) tensor in phosphate glasses can only be explained by using individual distributions parameters for the principal axes. A model is discussed, which assumes a linear dependency of such distributions from the principal values themselves. Furthermore, the influence of such distributions on magic angle spinning (MAS) spectra is investigated.

Determination of distributions of the quadrupole interaction in amorphous solids by 27Al satellite transition spectroscopy.

27Al Satellite transition spectroscopy (SATRAS) has been used to extract both the quadrupole interaction and its distribution width from MAS spectra of glasses. Using this method a measurement at a single magnetic field strength allows one to obtain the true chemical shifts and the quadrupole interaction (and its distributions) with high accuracy, including quantification of the results. In contrast to earlier investigations the central transition MAS lineshapes can be described without assumptions and give correct relative proportions of differently coordinated Al species in glasses.

27Al satellite transition spectroscopy (SATRAS) of polycrystalline aluminum borate 9Al2O3.2B2O3.

27Al NMR spectra of polycrystalline aluminum borate 9Al2O3.2B2O3 have been measured at 104, 130 and 156 MHz. The parameters of the quadrupole interaction and the isotropic chemical shifts have been obtained by fitting the CT/MAS pattern and consideration of the inner satellite transitions m = 3/2<-->1/2 and m = - 1/2<-->- 3/2.