Structural Characterization of and Phase Separation in Vanadate Glasses

Abstract

Structural characterization of vanadate glasses, an essential but often neglected step in studying physical properties of nonperiodic solids, has been carried out in the composition range 70.0–87.5 mole % V₂O₅, the remainder being P₂O₅, by bright‐field, dark‐field, and diffraction electron microscopy. Replicas and powdered chips of bulk samples gave inconclusive results, and thinning techniques were not attempted due to difficulties associated with the water solubility of the material. Blown, thin films were suitable for electron microscope study, any crystals occurring in the films being of dimension 20 Å or less and not readily detectable. Liquid‐liquid immiscible regions, possibly due to phase separation by the spinodal mechanism, were observed in the 87.5 mole % V₂O₅ films but not in films of other compositions.