High-resolution ²⁷Al, and ²⁹Si NMR spectroscopy of glasses and crystals along the join CaMgSi₂O₆-CaAl₂SiO₆.

High-resolution magic-angle sample-spinning (MASS) ²⁷Al and ²⁹Si NMR spectroscopic data for glasses and crystals along the join: CaMgSi₂O₆-CaAl₂SiO₆(Di-CaTs) are presented and analysed. The results indicate that the glasses become increasingly polymerized with increasing CaTs content, that CaTs glass is fully polymerized, and that the lack of variation in the ²⁹Si chemical shift is due to the opposing effects of increasing polymerization, which increases shielding, and the increasing number of Al next-nearest neighbours, which decreases the shielding.-J.A.Z.