In the present work, ZnO–Bi2O3–P2O5 glasses were studied to examine the effect of the Bi2O3 composition on the structure and properties of the phosphate glass system. Glasses with the compositions, I: (50 − 2x)ZnO–xBi2O3 − (50 + x)P2O5 and II: (50 − x)ZnO–xBi2O3–50P2O5(x = 0 − 20 mol%) were prepared. To investigate the relation between the structural change and compositional change, the structure was measured by FT-IR analysis and the density, glass transition temperature (Tg) and chemical properties of the glasses were measured. The Tg and chemical properties (water-resistant qualities) increased with increasing metaphosphate phase in the glasses, due to the increase in the number of bridging oxygens. The glass properties were dependent on the O/P ratio. The compositional variations that changed the dominant phosphate structure from a metaphosphate to a pyrophosphate were accompanied by the transformation in the dominant Bi coordination, complicating the effect that Bi2O3 has on the glass properties. Bi3+ cations were incorporated into the glass network and difference in the Bi–O bonding state in the glasses.
