Ascendancy of Cr2O3 on morphology, spectroscopic and dielectric properties of GeO2–Li2O–P2O5–MgO glasses

The dielectric, physical, and optical properties of 5GeO2–30Li2O–55P2O5–(10-x)MgO–xCr2O3 (x varies from 0 to 0.9 mol%) glasses were investigated. The specimens were synthesized using melt quenching and heat treatment techniques. The non-crystalline behavior of the specimens was analyzed by X-ray diffraction. The physical parameters of these glasses were also determined. These parameters indicate the compact nature of the glasses. The optical absorption spectra of the specimens show bands corresponding to Cr3+ ions. The optical band gap (Eg) and Urbach energy (ΔE) of glasses were evaluated. Fourier-transform infrared and Raman spectra showed typical bands related to the phosphate species and supported the structural changes in the glasses. The emission and electron spin resonance (ESR) spectra confirmed the presence of chromium ions (Cr3+ state) in the glasses. An increase in the intensity of the ESR resonance signals and emission bands suggested an increase in the number of chromium ions. The dielectric parameters of the samples are also determined.