Structural, optical and electrical investigation of sodium phosphate glasses doped MoO3 for high power visible laser safety

Abstract

Phosphate glasses with the chemical composition of 47P2O5–24ZnO-(29-x)Na2O-xMoO3, x = 0, 2, 4, 6, 8 and 10 mol%, has been prepared using the melt quenching technique. The amorphous nature of these glasses is confirmed using XRD spectra. The density and molar volume of all glasses are experimentally measured and theoretically calculated. The influence of the replacement of MoO3 with Na2O on the FTIR spectroscopy of the investigated glasses is studied. The FTIR investigation reveals that in the glasses with x = 4, 6 and 8 mol%, the absorption band 1260 cm−1 related to the Q2 phosphate structural units is more sensitive to sodium cations than molybdenum cations. In the same region, x = 4–8 mol%, the temperature dependence of the dc conductivity of these glasses deviates from the Arrhenius law and obey the Meyer-Neldel Rule. The optical transmission spectra, measured in the wavelength range from 200 to 2500 nm, reveal that the glasses containing MoO3 greater than 4 mol% are suitable for shielding the radiation of the high power lasers operating in the visible region and, in turn, verifying the safety from these lasers. The dc conductivity of the investigated glasses is found to be a combination of two contributions: ionic conduction that is due to the movement of the mobile sodium ions and electronic conduction that is due to the electron hopping between molybdenum ions. The increase of the molar volume with increasing MoO3 content makes the ionic contribution to the conduction process more effective because of the enhancement of the mobility of sodium ions.