A comparative study of the experimental and the theoretical elastic data of Tm3þ doped zinc borotellurite glass

A series of glass samples with composition {[(TeO2)0.7(B2O3)0.3]0.7[ZnO]0.3}1-x{Tm2O3}x was prepared by using the melt-quenching technique. Then, the samples were characterized by using the densimeter, FTIR and ultrasound technique. The variations of density, molar volume, ultrasonic velocity, elastic moduli,and Poisson’s ratio were discussed and correlated with the composition of the glass samples and the FTIR spectra. It was found that the addition of thulium caused bridging and non-bridging oxygen to be formed at the same time due to the different effect that occur to tellurite and borate network as thulium is added. As thulium is varied from 1 until 3 mol%, bridging oxygens had been found to occur at a high rate and caused the ultrasonic velocity to increase. Nonetheless, when thulium oxide exceeded 3 mol%, nonbridging oxygens formed at a high rate. As a result, ultrasonic velocity was reduced. Furthermore, the values of elastic moduli (including bulk, shear, Young’s modulus, and Poisson’s ratio) were compared with the data that were calculated theoretically by using bulk compression, Makishima-Mackenzie, and Rocherulle models

Structural and optical properties of Tm2O3-doped zinc borotellurite glass system

Thulium doped zinc borotellurite glasses with composition {[(TeO2)0.7(B2O3)0.3]0.7[ZnO]0.3}1-x{Tm2O3}x were synthesized using melt-quenching technique. The values of x varied from 0.01 to 0.05 mol. The density and molar volume of the glass samples were found to increase with increased concentration of thulium oxide. FTIR analysis showed the existence of TeO4, BO3 and BO4 structural units in the glass network as well as the formation of bridging oxygens. XRD patterns confirmed the amorphous nature of the glass and were supported by the absence of sharp edges in the absorption spectra. All the optical data was found to vary with the concentration of Tm2O3. The direct and indirect optical band gap was in the range of 4.19 to 4.38 eV and 3.62 to 3.79 eV respectively. The trend for refractive index, molar refraction and molar polarizability was in opposite trend to the optical band gap and Urbach energy due to the variation of non-bridging oxygens (NBOs), increment of cross-link density, and also the existence of free electrons in the glass system

The effect of erbium oxide in physical and structural properties of zinc tellurite glass system

In this research, the melt-quenching method was used to synthesize a series of zinc tellurite glass systems doped with erbium oxide with the chemical composition of [(TeO2)0.7 (ZnO)0.3]1−x (Er2O3)x at different molar fraction, x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05. X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, density, molar volume, elastic and optical measurements were used to characterize the prepared glass samples. At room temperature, the result of the XRD, FTIR, density, elastic and optical properties were all recorded. An amorphous nature of glass samples is proven by the XRD spectra. The analysis of FTIR spectra shows the presence of functional vibration of tellurite network. It is observed that the density of the glass system increase with the molar fraction of Er2O3. The value of molar volume is found to be directly proportional to the density. Thus, the increment in the density value causes the increment of the molar volume due to the increase of erbium concentration. This in turn results in the creation of excess free volume due to the difference of atomic radius between erbium and tellurite. On the other hand, ultrasonic velocity was used to determine the elastic moduli of the glass systems. The elastic moduli such as longitudinal modulus, shear modulus, bulk modulus and Young's modulus give a fluctuating trend against the concentration of Er2O3. The increase of the elastic moduli is due to the mix former effect. In contrast, the decrease of the elastic moduli is due to the breakdown of Er2O3 in the zinc tellurite glass system which weakens the glass structure of the ternary tellurite system. The optical properties of the prepared glasses were determined by UV–vis analysis. The optical absorption was recorded at room temperature in the wavelength ranging from 220 nm to 800 nm. The optical absorption spectra reveal that fundamental absorption edge shifts to higher wavelength as the content of erbium oxide increase. The values of direct and indirect band gap have been calculated and are observed to decrease with the increase content of erbium oxide. However, the Urbach energy, refractive index, molar refraction and electronic polarizability are shown to be increased with an addition content of erbium oxides