[(TeO2)0.8 (B2O3)0.2]0.8 (SiO2)0.2}0.99 (Ag2O)0.01]1-y - (Er2O3 NPs)y, and y=0.01,0.02,0.03,0.04 and 0.05 mole% were fabricated by the melt quenching technique. X-ray diffraction (XRD) was used to verify and confirm the glasses’ non-crystallinity. X-ray fluorescence (XRF) proved the achievement of silicate of 98.6% quality from rice husk. Fourier transform infrared d (FTIR) results exposed the basic structural units such as TeO4, TeO3, BO4, BO3, Si-O-Si, and O-Si-O within the network. The concentration of Er2O3 nanoparticles’ effects on the thermal properties of ErDBST glasses was duly discussed. From the profiling of the differential scanning calorimetry (DSC), the glass crystallization temperature Tc, and transition temperature Tg are estimated. Also, the thermal stability factor, defined as Ts = Tc - Tg, was higher than 100 oC. From room temperature above the Tg for all the sample glasses, specific heat capacity Cq (≥1.4 J/gK-1) was obtained. The results showed that the glass thermal stability and the transition temperature increase with the addition of Er2O3 nanoparticles (NPs). These suggest that an ErDBST glass exhibit good thermal stability and consequently is a suitable candidate for fiber drawing. تفاصيل المقالة

This work deals with the theoretical analysis of ultrasonic relaxation in the glass system xNb2O5 (100− x) TeO2 glasses, and 4 ≤ x ≤22.5 mole %. The parameters of the theoretical analysis deal with the transmission of ultrasonic waves through dual-well potential. The parameters are alternate potential energy, centers of energy loss, and elongation or contraction of the two-well potential. Moreover, the deformation potential is found to be sensitive to the variations of the Nb2O5 content. The number of centers of energy loss is related to the elastic moduli as a function of Nb2O5 content. The analysis revealed a sensitive effect of variation of Nb2O5 contents for elongation or contraction of the dual-well potential. Due to the increase of Nb2O5 from 4 to 22.5 mole %, the potential energy changed from 4-92 to 5.06 eV, longitudinal and transverse deformation potential changed from 0.18 to 0.346 and from 0.06 to 0.141 eV, respectively. The increase in the deformation potential of the presented dual-well state could be attributed to the increase of the experimental elastic parameters like Young’s and shear moduli of the present glasses. تفاصيل المقالة

Samarium oxide (Sm2O3) and ytterbium oxide (Yb2O3) doped tungsten-tellurite glasses (TWSm), (TWYb) in the forms of 80 (TeO2) - (20-x) (WO3) - x (Sm2O3) and 80 (TeO2) - (20-x) (WO3) - x (Yb2O3) with x = 0, 1.0, 2.0, 3.0, 4.0 and 5.0 mol% were prepared by the melt-quenching technique. The XRD analysis for the two prepared glass systems verified the samples’ amorphous nature. The glass density ( ρ ) was measured by the Archimedes method. Both ( ρ ) and the molar volume (VM) of the two prepared systems showed an increase with increasing the concentrations of dopants Sm3+ and Yb3+. Longitudinal VL and shear VS wave velocities were measured at 5 MHz frequency using the pulse-echo technique. Longitudinal (L), shear (G), bulk (K), and Young’s moduli ( E ) have been founded. Moreover, Poisson’s (σ), Debye temperature (θD), softening temperature (TS), micro-hardness (H) have been founded for every glass sample. Elastic moduli showed an increase with increasing dopants concentration of (Sm2O3) or (Yb2O3). Moreover, the bulk modulus of (TWSm) glasses was higher than (TWYb) glasses. Mechanical properties of (TWSm) and (TWYb) are crucial parameter in manufacturing optical fibers. تفاصيل المقالة

AbstractThe study of optical and thermal properties of gadolinium oxide-doped tellurite glass was studied for the first time to the best of our knowledge. Gadolinium oxide-doped tellurite glass system with chemical formula (1 − x)[(TeO2)70(B2O3)30]-x(Gd2O3) with x = 0.2, 0.4, 0.6, 0.8 and 1.0 mol% was prepared by the melt-quenching technique. X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy and EL X-02 high-precision ellipsometer have been carried out. The thermal diffusivity of the amorphous material was studied using laser flash method. The microanalysis of major elements in the glass was examined by employing energy-dispersive X-ray spectrometry. The IR of the glass matrix denotes three obvious absorption bands which are assigned to TeO4, BO3 and BO4 vibrational groups. The addition of Gd ions enhances the refractive index of the tellurite glass. The optical band gap and Urbach energy were determined based on the absorption spectra. It is found that the Gd ions reduce the optical band gap energy. The thermal diffusivity of the glass samples follows nonlinear trend with the concentration of Gd ions. Electronic polarizability, optical basicity and metallization criterion have been calculated for every glass composition. Based on these results, the proposed materials have high potential to be applied in photonic materials. تفاصيل المقالة