Structure, glass transition temperature and spectroscopic properties of 10Li2O–xP2O5–(89 − x)TeO2–1CuO (5 ≤ x ≤ 25 mol%) glass system

X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectrometry (EDS), differential scanning calorimetry (DSC), infrared (IR), Raman, electron paramagnetic resonance (EPR) and optical absorption studies on 10Li2O–xP2O5–(89 − x)TeO2–1CuO glasses (where x = 5, 10, 15, 20 and 25 mol%) have been carried out. The amorphous nature of the glasses was confirmed using XRD and FESEM measurements. The glass transition temperature (Tg) of glass samples have been estimated from DSC traces and found that the Tg increases with increasing P2O5 content. Both the IR and Raman studies have been showed that the present glass system consists of [TeO3], [TeO4], [PO3] and [PO4] units. The spin-Hamiltonian parameters such as g∥, g⊥, and A∥ have been determined from EPR spectra and it was found that the Cu2+ ion is present in tetragonal distorted octahedral site with dx2−y2dx2−y2 as the ground state. Bonding parameters and bonding symmetry of Cu2+ ions have been calculated by correlating EPR and optical data and were found to be composition dependent.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Glasses in the Li2O–P2O5–TeO2–1CuO system have been prepared using the melt quenching technique. ► FESEM micrograph has confirmed the amorphous nature of the glass. ► A variety of spectroscopic (IR, Raman, EPR and optical absorption) tools have been employed for glass characterization. ► IR and Raman studies revealed that the present glass system consists of [TeO3], [TeO4], [PO3] and [PO4] units. ► The glass transition temperature (Tg) increases with increasing P2O5 content.