Viscosity in the range of 10 7 and 10 11Pas was measured by a penetration method for barium phosphate and borophosphate glass melts in a series of xB2O3-(100-x)Ba(PO3)2 where x=0-12mol%. The viscosity at a certain temperature increases with increasing B2O3 concentration. The variation of viscosity with B2O3 concentration is qualitatively related to glass structure reported in previous studies. The immersion test into distilled water for glass plates reveals that B2O3 addition degrades water durability. The microstructure observation reveals the precipitation of many nano-sized particles at the immersed surface of a barium borophosphate glass. No spectral change of Nd3+ absorption was observed in between binary barium phosphate and ternary barium borophosphate glasses due to the site selectivity of Nd3+ ions with PO4 networks.
