Synthesis and structural characterization of dry AgPO3 glass by Raman scattering, infrared reflectance, and modulated differential scanning calorimetry
چکیده
The glass transition temperatures of AgPO3 have been reported to lie in the 163 Tg 192 °C range. These results are typical when precursors are processed at laboratory ambient. In the present work, we show that if precursors are handled in a dry ambient environment, the Tg’s steadily increase in the 181 2 Tg 254 2 °C range as the relative humidity of the ambient environment decreases. The glass transition temperature of dry AgPO3 is found to be 254 2 °C. We have compared the vibrational densities of states of the low-Tg 181 2 °C and high-Tg 254 2 °C samples in Raman scattering and ir reflectance measurements. The ir reflectance shows the presence of both free and bonded water in the low-Tg 181 2 °C samples, but the concentration of both species decreases in the high-Tg 254 2 °C samples. In Raman scattering, the boson peak scattering strength increases, and the scattering strength ratio R of the P-Ot terminal to the P-Ob bridging mode of the P-O-Pchains decreases as the sample Tg increases. The presence of bonded water serves to scission the P-O-P chain network by replacing bridging Ob oxygen sites with terminal OH − species; and once incorporated, bonded water is difficult to remove.