Effect of alkali and alkaline earth fluoride introduction on thermal stability and structure of fluorophosphate glasses

The thermal stability and structure of RF–RF2–AlF3–Al(PO3)3 fluorophosphate glasses were investigated. Analyses of infrared absorbance spectra and Raman spectra reveal that with increasing number of alkali and alkaline earth fluoride components, the sum of POP bond and OPO bond increases and glass network is strengthened. Consequently, the inhibition to nucleation and crystallization processes is improved, which is proved by the increment of thermal stability factors ΔT and S determined by differential scanning calorimetry. In addition, it was found that LiF has poor ability to form glass in univalent alkali fluorides and MgF2 has comparative strong ability to form glass in bivalent alkaline earth fluorides.