Solid State (31)P/(27) Al and (31)P/(23)NA MAS NMR Dipolar Dephasing Investigations of Connectivity in Sodium Aluminophosphate Glasses;The Journal of Physical Chemistry B

摘要

Solid state (31)P/(27)Al and (31)P/(23)Na MAS NMR dipolar dephasing experiments have been used to investigate the spatial distribution of aluminum and sodium cations with respect to the phosphate backbone for a series of sodium aluminophosphate glasses. From the (31)P/(27)Al and (31)P/(23)Na connectivity data gathered, information about the medium range order in these glasses is obtained. The expanded connectivity data allows for better identification and interpretation f the new resonances observed in the (31)P MAS NMR spectra with the addition of alumina. The results of the dipolar dephasing experiments show that the sodium-phosphate distribution remains relatively unchanged for the glass series, and that the addition of aluminum occurs primarily through the depolymerization of the phosphate tetrahedral backbone.