Fluorophosphate glasses containing manganese

International audienceNew fluorophosphate glasses based on MnF2, NaPO3 and MFn (M=Zn2+, Sr2+, Mg2+, Ba2+, Li+, Na+ and K+) have been synthesised and characterized. Large vitreous areas were observed. Samples of 4 mm in thickness have been obtained. These glasses are easy to prepare and stable in ambient air. Depending on the composition and the nature of the M cation, glass transition temperature, Tg, lies between 230 and 314 °C, crystallisation temperature, Tx is between 320 and 475 °C. These glasses are pink coloured, and infrared transmission extends up to 4.5 μm with extrinsic OH− absorption band at 3200 cm−1 and other bands around 2200 and 1600 cm−1 that relate to PO4 tetrahedron vibration. Other physical properties including density, microhardness, Young modulus, thermal expansion and refractive index were investigated and correlated to composition

Fluoride glasses based on the ZrF4 - BaF2 - MnF2 system

International audienceGlass formation has been studied in the ZrF4-BaF2-MnF2 ternary system. Two different vitreous areas have been observed. One of them corresponds to high concentrations in manganese fluoride, which confirms the vitrifying ability of MnF2. The stability of these glasses versus devitrification has been increased by the incorporation of AlF3 and ZnF2. Glass compositions and partial vitreous areas are reported in the ZrF4-BaF2-MnF2-AlF3-ZnF2 system. The evolution of characteristic temperatures and density versus chemical composition has been studied. These glasses have a potential for phoinduced phenomena

Physical properties and magnetic susceptibility studies of fluorophosphate glasses based on manganese

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New heavy metal oxide glasses based on Sb2O3

International audienceAntimony glass formation commonly requires conventional glass former such as oxides of silicon, germanium, boron or phosphorus or halides such as PbCl2, ZnCl2 or ZnBr2. Recently, a new family of glasses based on the binary systems Sb2O3-M2O (M=Li, Na and K) are reported. Ternary glasses synthesized in vitreous carbon and silicate crucibles were obtained in the combination Sb2O3-Na2O-(PbO or MoO3). Characteristics temperatures of these glasses have been measured using differential thermal analysis (DSC). Glass transition temperature, Tg, ranges from 539 to 555 K and the thermal stability range (Tx-Tg) lies between 31 and 95 K for binary glasses in the Sb2O3-MoO3. The incorporation of alkali oxides Na2O in ternary systems Sb2O3-Na2O-(PbO or MoO3) gives large vitreous area and enhances the stability of antimony glasses. Samples are red in binary Sb2O3-MoO3 and turn yellow by the addition of the alkali oxide. These glasses are opaque to UV light since they absorb radiation near 380 nm. Elastics moduli of these glasses were determined by the pulse-echo ultrasonic propagation. These glasses suggested having potential application as low phonon energy glasses for infrared transmission and hosts for rare earth ion in active devices

Synthesis and characterization of Er3+/Cu+-codoped fluorophosphate glasses

International audienceNaPO3-ZnF2 binary fluorophosphate glasses doped with trivalent erbium and monovalent copper were synthesized by the conventional melting and casting method using ErF3 and CuCl as starting materials. The samples were systematically investigated using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. X-ray powder diffraction patterns confirmed that the as-prepared compounds were all amorphous. The glass transition temperature (Tg) was observed around 230 °C by DSC analysis, while the thermal stability range (ΔT) was estimated to be between 90 and 140 °C. The measured value of the refractive index (n) was measured as 1.502 at a wavelength of 632.8 nm. Thermal annealing of the samples was performed at different temperatures above Tg for various heat-treatment times. During these steps, monovalent copper and sodium ions were expected to be reduced, forming metallic nanoparticles. This transformation lead to coloration changes, depending on the annealing time and temperature, with respect to the transparency of the glasses. These spectroscopic changes are related to the plasmonic effects induced by the presence of both Cu and Na metallic nanoparticles, which promote red shift due to absorption. The VIS-NIR absorption spectra of the prepared glasses were investigated in the frame work of standard Judd-Ofelt (J-O) theory, which was used to determine the J-O intensity parameters, radiative transition probabilities and branching ratios for Er3+ ions embedded in the glasses. The calculated intensity parameters () were compared to those obtained for Er3+ in several other glasses