PHYSICAL-PROPERTIES AND FRAGILITY OF X-M2O.(50-X)SRO.50P(2)O(5) GLASSES (M=AG,NA)

Some physical properties and fragility of glasses from xM(2)O. (50-x) SrO.50P(2)O(5) (M=Ag, Na) were examined. The oxygen packing density of the glasses decreased rapidly with increasing Ag2O content, i.e. with R(Ag2O) = Ag2O/(Ag2O+SrO), from 7.84x10(-2) mol/cm(3) for R(Ag2O)=0 t o 7.18x10(-2) for R(Ag2O)=1.0. The glass transition temperature was lo wered with increasing R(Ag2O) from 501 to 211 degrees C due to the dec rease in density of the glass network. Viscosity and activation energy for viscous flow of xAg(2)O. (50-x) SrO.50P(2)O(5) supercooled liquid s also decreased with increasing R(Ag2O). From the fragility concept t he supercooled liquids wish R(Ag2O)<0.4 become strong with increasing R(Ag2O) ratio due to the improvement in the thermal stability of inter mediate range order The difference in the contributions of Ag+ and Na for physical properties and fragility was also clarified.