Investigation of physical properties of Mn doped lead phosphate glasses

Mn doped lead phosphate glasses (MnLPG) as (40-x)%P2O5-40 % PbO-16.5%Na2O-3.5%Al2O3-xMnO2 (x = 0, 1, 2, 3 and 4 %) matrix system are prepared by the melt-quenching method. The physical properties have been performed using several techniques such as X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform InfraRed spectroscopy (FTIR), Raman spectroscopy, UV–Visible properties, photoluminescence (PL) and EPR (electron paramagnetic resonance). XRD confirms the amorphous character of the glasses. DSC reveals an improvement of the glass transition temperature Tg values by increasing the density ρ and the oxygen packing density OPD and decreasing the molar volume Vm which leads to have a network glass more compact and tightly packed and reticulates the phosphate groups. The Infrared and Raman results show an opposite behaviour with a broken of the phosphate structure and the disruption of the P–O–P linkages. The optical spectra present absorption bands characteristic of Mn3+ and Mn2+ ions octahedral transition. Mott and Davis model presents a decrease of the band gap energy winth the MnO2 addition. The Urbach energy ΔEurb shows an increase with increase of manganese amount which is related to the increase of the structural disorder degree as the rate of manganese increases. The EPR spectrum of the 4 % Mn doped glass is characterized by a strong resonance signal centered at g near 2.0 another weak signal at g∼4.3 with no hyperfine structure. PL spectra exhibit emission bands corresponded to the oxygen defects presented in the glass and the appearance of a new band assigned to the Mn2+ ions as high as Mn increases. The paper illustrates the Mn doped lead phosphate glasses (MnLPG) as 40 % PbO, 16.5 % Na2O3, 3.5 % Al2O3, (40-x) % P2O5, x MnO2 (x = 0, 1, 2, 3 and 4 %). These glasses are treated by their physical properties deduced from: X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform InfraRed spectroscopy (FTIR), Raman spectroscopy, UV–Visible properties, Electron Paramagnetic Resonance (EPR) and photoluminescence (PL):•The increase in density ρ and oxygen packing density OPD and the decrease of the molar volume Vm with increasing Mn ratio leads to the increase of the glass transition temperature Tg.•The IR and Raman spectroscopies reveal the presence of PbO6, AlO6, PbO4, AlO4 and MnO4 vibration modes. Moreover, Raman results prove the intermediate behaviour that plays the MnO2.•The optical absorption mea