Glass formation in the Sb2O3-CdCl2-SrCl2 ternary system

International audienceVitreous systems based on antimony oxide Sb2O3 have been investigated. The limits for glass formation are reported in the Sb2O3-CdCl2-SrCl2 ternary system, and in the Sb2O3-SrCl2-(0.5CdCl2 + 0.5ZnCl2) pseudo ternary system. Amorphous state is confirmed by XRD patterns. Thermal measurements implemented by differential scanning calorimetry show that Tg is above 300 °C. As a general trend, Tg increases with chloride content. These glasses have an extended transmission in the mid-infrared spectrum with a refractive index larger than 2. The influence of the CdCl2/Sb2O3 substitution on the physical properties has been studied in the (90 − x)Sb2O3-xCdCl2-10SrCl2 system: thermal expansion, Vickers microhardness, Young and bulk modulus decrease as cadmium concentration increases. An inverse dependence is observed for shear modulus. This behaviour is discussed in relation to structural hypothesis

Synthesis and physical properties of glasses in the Sb2O3-PbCl2-MoO3 system

International audienceLead chloroantimonite glasses form stable binary glasses that may accommodate numerous oxides or halides as a third component. Molybdenum trioxide is a glass progenitor leading to molybdate glasses. Ternary glasses have been synthesized and studied in the Sb2O3-PbCl2-MoO3 system. Compositional limits of glass formation are reported and two series of glass samples have been prepared corresponding to the general formulas: (90 − x)Sb2O3-xPbCl2-10MoO3 and (90 − x)Sb2O3-xMoO3-10PbCl2. Glass transition temperature is close to 290 °C at high Sb2O3 content and decreases as antimony oxide is substituted by MoO3 or PbCl2. Position, width and intensity of crystallization peak suggest that devitrification rate is small in some composition ranges. The evolution of density, thermal expansion, refractive index and microhardness has been studied as a function of composition parameter x. Deviations from linearity are observed. They suggest structural changes in the case of the MoO3/Sb2O3 substitution while it appears that molar volume increases linearly versus lead content in the other series of glasses. Refractive index is close to 2.04. Optical transmission ranges from 550 nm in the visible spectrum to 5.5 μm in the infrared. It is limited by extrinsic absorption bands arising from hydroxyls and silicon impurities. Young's, bulk and shear moduli have been measured for the two series of samples

Spectroscopic and Judd-Ofelt Analysis of Nd3+ Ion Doped Lithium Antimony-Borate Glasses for Visible and Near Infrared Laser Application Compared to Standard Emission at 1.06 μm

International audienceThe present work focuses on the spectroscopic luminescence analysis of trivalent neodymium-doped lithium antimony-borate glasses, with the glass composition 70 Sb2O3-(25-x) B2O3-5 li(2)O-x Nd2O3 where x = 0.3; 0.5; 0.7 mol% (SBLN). Around 475 nm excitation used by the transition I-4(9/2 )-> (2)G(9/2) + D-2(3/2) + K-2(15/2) and that induced emission lines of wavelengths lambda emis = 584;673;767;826 nm (red is low intensity). The specific emission follows the transitions (2)G(7/2) + (4)G(5/2b)-> I-4(J) (J = 9/2; 11/2; 13/2; 15/2). Previous work on Nd3+ doped glasses studied near-infrared emission in 4F3/2-> 4IJ mode (J = 9/2; 11/2; 13/2) via near-infrared excitation( 4)I(9/2)-> F-4(5/ 2)+H-2(9/2). The Judd-Ofelt analysis applied to SBLN glasses showed that the S2K parameters are consistent with the values in the literature. SBLN7 glass has the best spectroscopic factor Omega(4)/Omega(6) = 0.974; while the best luminescence branching ratio is that of the green emission and it stands at an average beta = 70%. Similarly, green emission has the best values of stimulated emission cross section and gain bandwidth. Calculated and measured lifetimes are ranged between 15 and 40 microseconds; however, quantum efficiency varies between 50 and 91%. In another side calculated and measured refractive index values are very close. The chromatic coordinates of observed green color showed accurately that lies in the yellowish-green region of the chromaticity diagram edited by CIE 1931. The calculation of its temperature was made by Mc Macy's equation, and it is in the limits of 5100 K; which corresponds to a cool color similar to midday sunlight

Influence of molybdenum oxide on structural, optical and physical properties of oxychloride glasses for nonlinear optical devices

International audienceThe unconventional Heavy Metal Oxide Glasses (HMOG) are characterized by a low phonon energy, large infrared range transmission, high refractive index and nonlinear optical properties. Ternary glasses have been synthesized and studied in the Sb2O3– MoO3-ZnCl2 system. Further, the glass formation compositional limits are reported and some glass samples with the formula: (90-x)Sb2O3 -xMoO3–10 ZnCl2 (10 ≤ x ≤ 50, mole%) were elaborated. Thermal properties have been measured and indicating that the glass transition temperature decreases with increasing proportions of molybdenum oxide. The evolution of density, microhardness and elastic modulus has been studied as functions of parameter x and Raman spectra measurements have been shown the partial conversion of MoO6 octahedral units into MoO4 tetrahedral

Spectroscopic analysis of up conversion luminescence in doped halogeno-antimonite glass

International audienceThe up-conversion emission of Nd3+, Sm3+ and Er3+ has been studied in a new halogeno-antimonite glass with the chemical composition 80 Sb2O3 – 10 ZnBr2 – 10 KCl. Doping concentration was 0.2 mol% of lanthanide (Ln) ions. Rare earths were introduced as fluorides LnF3 that were further converted into oxides. Main physical properties of base glass were measured, including density, thermal expansion, characteristic temperatures, refractive index and optical transmission. The amount of residual hydroxyls was calculated from the OH absorption band around 3000 nm. The recorded up-conversion emission lines are λem = 536 nm for Nd3+ pumped at 805 nm; λem = 563 nm, 600 nm, 631 nm and 645 nm for Sm3+ pumped at 945 nm; λem = 531 nm for Er3+ pumped at 798 nm. Co-doped glass (0.1 Yb3+ + 0.1 Er3+) pumped at 980 nm has three emission lines at 524 nm, 545 nm and 650 nm. Corresponding transitions have been identified and the mechanisms ruling the up-conversion process is discussed. They include excited state absorption (ESA), energy transfer (ET) cooperative energy transfer (CET), emission assisted by phonon (EAP), multiphonon relaxation (MR) and cross- relaxation (CR)

Optical and devitrification kinetic studies of chloro-antimonate glasses

International audienceIn this present work optical and devitrification studies of the synthesized 80 Sb2O3 –10 SrCl2 – 10 CdCl2 glasses were explored. The samples were annealed at temperature 455 °C by the different time range from 10 to 25 min with an interval of 5 min. All the synthesized samples have been characterized by spectroscopic techniques viz., UV–visible transmission, Fourier Transform Infrared transmission and Urbach plot was the complementary for the optical band gap calculation, finally the refractive index of the glass sample has been determined. The synthesized glass sample has a large optical window operating between 361 nm and 7.51 μm and has a high refractive index close to 1.7. The Urbach's plot shows that the optical band gap of the glass sample reaches a higher order value 3.25 eV. Scanning electron microscope (SEM) examination confirms that devitrification obeyed superficial mechanism, when controlled by the specific pre-nucleation process, which is based on self-creation of rough areas and the crystallization diffusion depth. On surface crystals formed in different morphologies like polyhedron; hemispherical (rarely); lath and needle. The progression of crystallization towards the interior is done layer by layer mode (nested lamellae) whereas the contour of the assembly is in a root mode. X-ray diffraction (XRD) pattern shows that the crystalline structure is composed of Valentenite. The kinetic parameters such as crystallization energy (150 kJ/mol) and the Avrami's (n = 3.405) index were calculated according to Chen's and Ozawa's methods. The attractive optical qualities and kinetic parameters indicate that the synthesized glass sample is a good stability against devitrification. © 2020 Elsevier B.V

Judd-Ofelt analysis and luminescence studies of Er3+ doped halogeno-antimonate glasses

International audienceThis research paper emphasized on application of Judd-Ofelt's (JO) theory for low doped erbium (0.2 mol%) halogeno-antimonate based glasses with molar composition (90 –x) Sb2O3 - x ZnBr2 - 10 NaCl (where x = 10, 20, 30 and 40 mol%). 80 Sb2O3 – 9.8 ZnBr2 - 10 NaCl - 0.2 Er2O3 glass sample has low phonon energy and high refractive index is a potential candidate for luminescence applications. Differential scanning calorimetry (DSC) measurements show good the thermal stability of the prepared glass samples and on the other hand density, expansion coefficient and elastic moduli were reported. Judd-Ofelt's (JO) parameter intensities Ω2 = 3.27 × 10−20 cm2, Ω4 = 1.24 × 10−20 cm2 and Ω6 = 1.88 × 10−20 cm2 were found and these were compared with the literature. Radiative parameters such as spontaneous emission rate, branching ratio and lifetime were calculated. We focused on a high branching ratio radiative transitions 2H11/2 → 4I15/2 (β = 0.94) and 4F9/2 → 4I15/2 (β = 0.901). The overlap between absorption and emission bands is partial and stokes type shifts were presented. The gain curves were determined after calculation of absorption and stimulated emission cross sections. The infrared transmission curve of the glass matrix was marked extrinsic absorption bands SiO and hydroxyl OH possessed high vibration energy played quenching effect for photoluminescence

Anomalous properties of chloroborosilicate glasses in the K2O-BaO-Al2O3-B2O3-SiO2-BaCl2 system

A series of chloroborosilicate glass having composition (in mol%) (100 -x)(42SiO(2)-30B(2)O(3)-20BaO-4K(2)O-4Al(2)O(3))-xBaCl(2) (where x = 0-30) has been prepared by the melt quench technique yielding transparent monolithic glasses up to x = 22.5. Structural investigation by infrared reflection and UV-vis-NIR absorption revealed the bridging action of Cl atom and decrease in non-bridging oxygens with the increase in BaCl2 content. Thermal properties (T (g), T (d) and T (s)) were measured by the dilatometry and softening point measurement. Viscosity was calculated using the Vogel-Fulcher-Tammann equation. Elastic constants were measured by the ultrasonic method. Other mechanical properties like hardness, fracture toughness were also measured. All of the thermal and mechanical properties exhibited a similar trend of anomalous variation as a function of the BaCl2 content, showing maxima at 10 mol% and a sharp increase at 25 mol% BaCl2 content. The anomaly has been explained by the structural point of view with the help of the aforementioned spectroscopic data