Reactive atmosphere synthesis of sol-gel heavy metal fluoride glasses

A glass based on ZrF₄ was synthesized by a combination of sol-gel and reactive atmosphere processing. Infrared spectroscopy and combustion analysis show that the fluorination process reduces the concentration of organic and hydroxide impurities. Chemical changes have occurred during fluorination; this is indicated by different x-ray diffraction traces and crystallization characteristics for the fluorinated sample compared to the oxide gel product. Chemical analysis from x-ray fluorescence indicates that the fluorinated gel is chemically similar to a melted glass of the same composition. Differential scanning calorimetry gives a glass transition temperature of 290 °C and a crystallization temperature of 390 °C. These values are consistent with those expected for a fluoride glass prepared by conventional methods.