Improvement of thermal and optical properties of lithium phosphate glasses by adding MgO

Collective characterizations of prepared lithium phosphate glass together with samples containing increasing added MgO contents (0–2 mol%) were carried out by differential thermal analysis (DTA), spectroscopic ellipsometry (SE) and photoluminescence (PL) measurements. From the DTA profile, the glass transition temperature T g and crystallization onset temperature T x are estimated. The thermal stability factor was higher than 100 °C suggesting that this glass exhibits a good thermal stability and consequently is suitable to be a potential candidate for fiber drawing. Furthermore, the variation of the ΔT as function of MgO contents has a minimum at 1 mol% of MgO. The refractive index and extinction coefficient data were obtained by analyzing the experimental spectra of tanΨ and cosΔ measured by SE. The complex dielectric functions (e = e 1 + ιe 2) of the samples were estimated from regression analysis. Some of the optical absorption parameters, such as high-frequency dielectric constant, e ∞, the average values of oscillator strength, S o, wavelength of single oscillator, λ o, plasma frequency, ωp, and relaxation time, τ, have been evaluated. The PL spectra of the MgO-doped glass under 325-nm excitation wavelength were studied. The dependence of PL spectra on doping concentration shows a quenching of the PL intensity for MgO concentration above 1 mol%. The variations of the photoluminescence intensity, thermal stability refractive index and optical constants gave an indication to use the prepared glasses for design of novel functional optical materials with higher optical performance.