고상 핵자기공명 분광분석을 이용한 비정질 Na 규산염 및 알루미노규산염 내 조성에 따른 등방성 화학적 차폐 변화 규명

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 23Na magic angle spinning (MAS) NMR. We also obtain 23Na isotropic chemical shift (δiso) 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 δiso decreases with increasing SiO2 content in Na silicate and aluminosilicate glasses. The δiso increases with increasing Na2O content in Na-Ca silicate and Na aluminosilicate glasses when the SiO2 content is fixed. Considering the δiso of Na aluminosilicate glasses available in the previous studies, together with the current simulation results, we confirm that the δiso has positive correlation with Al / (Al + Si). Those experimental results were reproduced better using Q mas 1/2 model. The disorder of Na in Na silicate and aluminosilicate glasses can be revealed through the simulation of 1D 23Na MAS NMR spectra using Dmfit program in a short time.