31P and 27Al MAS NMR investigations of some lead phosphate glasses

The 31P MAS NMR spectra were measured and analyzed for the two phosphate glasses that contain distinct metals (i.e., In or Ba), different amounts of PbO, and the same content of P2O5 and Al2O3. The 31P MAS NMR spectra for the two glasses have a single isotropic peak at −3.77 or −4.76 ppm, indicating that orthophosphate species are the dominant P sites in the glasses studied. The 27Al MAS NMR spectrum measured for the lead–barium–aluminum phosphate glass shows that the aluminum ions present in the glass are in 4-, 5-, and 6-fold coordination with oxygen and that the Al(OP)4 is the dominant moiety for the glass, suggesting the formation of orthophosphate species in the glass.