Phosphate glasses having composition, 40Na 2 O-10BaO-xB 2 O 3-(50-x)P 2 O 5 , where x = 0-20 mol% were prepared using conventional melt quench technique. Density of these glasses was measured using Archimedes principle. Microhardness (MH) was measured by Vicker's indentation technique. Structural studies were carried out using IR spectroscopy and 31 P and 11 B MAS NMR. Density was found to vary between 2⋅ ⋅62 and 2⋅ ⋅77 g/cc. MH was found to increase with the increase in boron content. 31 P MAS NMR spectra showed the presence of middle Q 2 groups and end Q 1 and Q 0 groups with P-O-B linkages. FTIR studies showed the presence of BO 3 and BO 4 structural units along with the depolymerization of phosphate chains in conformity with 31 P MAS NMR. 11 B NMR spectra showed increase in BO 4 structural units with increasing boron content. The increase in MH with B 2 O 3 content is due to the increase of P-O-B linkages and BO 4 structural units as observed from MAS NMR studies resulting in a more rigid borophosphate glass networks.

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