Glass Transition and Fragility of Iron Phosphate Glasses.: II. Effect of Mixed-alkali

摘要: Abstract Changes in the heat capacity from glass state (Cpg) to supercooled liquid (Cpl), ΔCp=Cpl−Cpg, ratio of capacities, Cpl/Cpg, width transition temperature, ΔTg, and activation enthalpy for structural relaxation, Δ H ∗ , region xNa2O–(20−x)R2O–32Fe2O3–48P2O5 (R=K Cs) mol% glasses, where x=0, 5, 10, 15, 20, have been investigated using differential scanning calorimetry. ΔCp Cpl/Cpg are range 57–68 J/mol/K 1.41–1.51, respectively, which suggests that alkali-containing iron phosphate similar alkali-free binary glass, also belong category fragile liquids. Adding 20 alkali oxides 40Fe2O3–60P2O5 (mol%) composition does not change behavior or melt fragility very much, but increase Tg. No mixed-alkali effect is observed on any properties glass.