Structural units and properties of BaF2-PbF2-B2O3 glasses

The crystalline phase in 45PbF2 ⋅ 55B2O3 glass contains ordered clusters of former PbF2 units. Initial stages of cluster formation are shown in the figure. Clusters of size up to 9 nm appear in zone #2, which evolve in the surrounding matrix (zone #1).325