Effect of Composition on Isotropic Chemical Shift of Na Silicate and Aluminosilicate Glasses Using Solid State NMR

Probing the Na environments in Na silicate and aluminosilicate glasses is essential to the macroscopic properties of melts in the Earth. In particular, exploring the atomic structure of Na silicate and aluminosilicate glasses reveals Na-O distance, which plays an important role in transport properties of melts. Here we report the local environment around Na using Na magic angle spinning (MAS) NMR. We also obtain Na isotropic chemical shift (δ) of Na silicate and aluminosilicate glasses with varying composition using Dmfit program. The Q mas 1/2 model simulates the experimental results with three simulated peaks while the CzSimple model simulates with one peak. The δ decreases with increasing SiO2 content in Na silicate and aluminosilicate glasses. The δ increases with increasing Na2O content in Na-Ca silicate and Na aluminosilicate glasses when the SiO2 content is fixed. Considering *Corresponding author: +82-2-877-3072, E-mail: psy2325@snu.ac.kr (Present address: Korea Polar Research Institute, Incheon 21990, Korea)