Effect of redox state of copper on the properties of P 2O 5–Na 2O–CuO glasses

Abstract

Properties and redox state of copper in glasses with composition 50P 2O 5–20Na 2O–30CuO (mol%) melted with various conditions were is oxygen studied. X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared (FTIIR) spectroscopy were used to investigate the glass structure and determine the [Cu 2+] ratio ([Cu 2+] /[Cu total]) of the glasses. Cu 2P 3/2 XPS spectrum analyses revealed that the [Cu 2+] ratio increases with increasing melting time. The [Cu 2+] ratio in the glasses melted in oxygen atmosphere is higher than that melted in air. The smaller ionic size and the greater field strength of Cu 2+ ion result in smaller bond angle in P–O–P and PO 2 bonds as well as greater Cu–O bond force. When the [Cu 2+] ratio is increased, the density, hardness, T g, T d and chemical durability are elevated, but the thermal expansion coefficient is decreased. The relative concentration of bridging oxygen decreases with increasing the [Cu 2+] ratio. Thus, the phosphate chain length will be shortened and the glass structure will be tighter.