Researchers from the Shanghai Institute of Optics and Fine Mechanics (SIOM) of the Chinese Academy of Sciences (CAS) have prepared a P-Sn-O-Cl-N glass system at 350 °C and explored its structural properties.

Related results were published in Journal of Non-Crystalline Solids on June 6. 

Phosphate glass has potential applications in aspheric glass forming, low temperature encapsulation, photonic conversion and organic composite materials due to its low glass transition temperature.

Chlorophosphate glass has the combined advantages of phosphate and halide glass, such as high thermal expansion coefficient, strong resistance to devitrification and low phonon energy. The melting temperature can influence the formation and properties of low-melting glass. However, the effect of melting temperature on the properties of Sn-P-O-Cl-N glasses prepared below 500 °C remains unknown.

The research team used the traditional melt extraction cooling method to prepare the P-Sn-O-Cl-N colorless transparent glass system below 500 °C. By comparing the color, transparency and chemical stability of the samples, they found that the optimal melting temperature was 350 °C, and the glass exhibited an ultra-low glass transition temperature of <140 °C.

Moreover, the researchers found that the transparency, composition and structure of glasses prepared at lower temperatures were significantly different from those above 500 °C. Low temperature melting reduced the volatilization of Cl- and NH₄⁺ ions in the batch, thereby lowering the melting point and Tg of the glass.

The new low-melting glass prepared in this study provides new ideas for aspheric shaped glass, matrix glass for perovskite quantum dots, and low-melting functional material-doped glass. 

Sn-P-O-Cl-N glass prepared at different temperatures. (Image by SIOM)