Thermal stability and effect of heat treatment on manganese doped silica borotellurite glass

Glasses with chemical formula of {[(TeO2)0.7(B2O3)0.3]0.8[SiO2]0.2}1-x{MnO2}x where x = 0.00 ≤ x ≤ 0.05 molar fraction were fabricated using melt quenching technique. The temperature used in the heat treatment process of the glass sample is 600?C. Calorimetric measurement had been carried out to study the thermal properties of the fabricated glass. The crystallization kinetics of the glass system we reexamined under non-isothermal conditions via differential scanning calorimetric (DSC). The glass transition (Tg), onset glass transition (To), maximum crystallization temperature (Tc) and melting temperature (Tm) were determined. Results from DSC proved that the studied glasses have good thermal stability (Ts) in which indicates its high resistance to devitrification. Strong indicator for the glass forming ability of a glass material, Hurby parameter (Kgl) was also calculated in this research

Structural and optical properties of zinc borotellurite glass co-doped with lanthanum and silver oxide

A series of zinc borotellurite glass co-doped with lanthanum and silver oxide with the chemical formula of [{[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}0.96(La2O3)0.04]1-x(Ag2O)x where the molar frac-tion of silver oxide, x = 0.02, 0.04, 0.06, 0.08 and 0.10 had been successfully prepared via the conventional melt-quenching technique. The structural properties of the glasses were unveiled through X-ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy while optical properties of the glasses were investigated with Ultra Violet Visible (UV-Vis) spectropho-toscopy. The short range periodic atomic arrangement in the glass matrix that implies the amorphous nature of the glass was confirmed with the presence of a broad hump in the XRD pattern. On the other hand, the three absorption bands observable in the FTIR spectra had proven the existence of BO4, BO3 as well as TeO4 units in the glass network. The absorbance values retrieved from UV-Vis spectroscopy were utilized to calculate the indirect energy band gap and Urbach energy values of the fabricated glass. By employing the equations proposed by Mott and Davis, the obtained indirect energy band gap have val-ues ranging from 2.16 to 4.16 eV.The decreasing trend in indirect energy band gap and increasing Urbach energy values were related to the increasing num-ber of nonbridging oxygen (NBO) in the glass that is created from the breaking of Te-O-Te or B-O-B bonds after lanthanum as well as silver oxide are incor-porated into the zinc borotellurite glass network

Thermal stability, structural and optical properties of rice husk sillica borotellurite glasses containing MnO2

The quaternary glass system {[(TeO2)0.7(B2O3)0.3]0.8[SiO2]0.2}1-x{MnO2}x where x = 0.00, 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction was prepared by melt quenching technique. The amorphous nature of the glass is confirmed by X-ray diffraction patterns and Scanning Electron Microscopy(SEM). The prepared glass samples had also been characterized by Differential Scanning Calorimetry(DSC). The glass transition(Tg), onset glass transition(To), crystallization(Tc) and melting temperature(Tm) values were measured from DSC thermo-gram. Results from DSC indicate good thermal stability and low value of fragility (F) of the prepared glass samples. Thermal stability(Ts), Hurby parameter(Kgl), fragility(F) and activation energy(Ea) were calculated for every glass composition. It is observed that the optical band gap decreases with the concentration of MnO2. On the other hand, the refractive index(n) is observed to increase as the concentration of MnO2 increases. Fourier Transform Infrared (FTIR) spectroscopy has been done to identify the functional group in glass sample

Influence of manganese doping on elastic and structural properties of silica borotellurite glass

The quaternary glass system tellurium dioxide, boron trioxide, silicon dioxide and manganese dioxide where x = 0.00 to 0.05 M fraction has been successfully prepared via conventional melt and quench-casting technique. The density was determined by Archimedes method with distilled water as buoyant liquid. The results showed that the density decreases and molar volume increases with respect to manganese concentration. FTIR spectral studies suggest that glass network is mainly built up of boron trioxide, tetrahedral boron, tellurium trioxide, trioxotellurate and silicon dioxide structural units. The ultrasonic velocities and elastic moduli were recorded using a pulse-echo method at frequency 5 MHz at room temperature. Some other physical properties such as Debye temperature, softening temperature, microhardness, Poisson's ratio, fugacity, fractal bond connectivity and Cauchy relation were determined. Results indicate that these parameters depend upon the composition of the glass system and the dopant concentration, MnO2 inside the glass system

Comprehensive study on the nonlinear optical properties of lanthanum nanoparticles and lanthanum oxide doped zinc borotellurite glasses

Recently, the rapid growth in photonic field has increased the demand for nonlinear materials with higher performance and greater efficiency. Hence, a thorough investigation on the nonlinear optical properties of materials are essential and need to be done for possible future application of the material in photonic field as optical limiting or optical switching devices. Thus, through this research, the crucial parameters in nonlinear optical properties of zinc borotellurite glasses doped with lanthanum oxide and lanthanum nanoparticles were studied and investigated extensively. The two series of glasses were successfully fabricated via conventional melt-quenching technique. The fabricated samples were characterized by using Fourier Transform Infra-Red (FTIR) spectroscopy as well as Z-scan technique in order to study the structural and nonlinear optical properties of the glass systems. The existence of various amount of TeO4, TeO3, BO4 and BO3 in all the prepared glasses are proven through the observable absorption bands in the FTIR spectra. Inconsistent trends recorded for both nonlinear absorption coefficient and nonlinear refractive index might be associated with the simultaneous creation of bridging as well as nonbridging oxygen which eventually affect the values for both parameters. The figure of merit of the prepared glasses with values ranging from 0.055 to 0.267 which are smaller than one hints that the glass materials possess potential to be employed as all optical devices. 0.03 M fraction of lanthanum nanoparticles doped zinc borotellurite with FOM value larger than 1 has proven the ability of the respective glass to be employed as efficient all optical switching devices. The determined nonlinear optical parameters of the glasses should be able to provide sufficient and useful information on the fabricated glass samples for future application in photonic field

Structural, optical and thermal properties of Er3+-Ag codoped bio-silicate borotellurite glass

In this paper, thermal, structural and spectroscopic properties of Er3+-Ag+ codoped bio-silicate borotellurite [{[(TeO2)0.8 (B2O3)0.2]0.8 (SiO2)0.2}0.99 (Ag2O)0.01]1-y (Er2O3)y where y = 0.05 glass are studied. The thermal and structural studies have been conducted using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) respectively so as to confirm the nature of the glass sample. The Fourier transform infrared (FTIR) has revealed the basic structural units of the glass system. Ultra violet visible (UV–Vis) spectrometer was used to measure the absorption spectrum and was analysed using Judd-Ofelt (J-O) and McCumber theory. Other important parameters such as radiative lifetime, branching ratio and transition probability are also determined from the analysis. The peak emission cross section discovered from McCumber theory is 4.9 × 10−21 cm2 . This value is larger than that of phosphate, silicate and tellurite glasses. The gain band width and figure of merit are used to evaluate the application of the glass in optical amplification and solid state laser

Structural and optical properties of samarium doped silica borotellurite glasses for optical switching application

The quaternary 56TeO2-24B2O3-(20-x)SiO2-xSm2O3 (x = 0.01, 0.02, 0.03, 0.04 and 0.05 M fraction) glasses were fabricated by using melt quenching method. XRD analysis reveals the amorphous nature of the prepared glass samples. FTIR and deconvolution studies show that Sm2O3 influences the modification of the glass network in the silica borotellurite glass system. The optical band gap and Urbach energy increases and decreases respectively with the addition of Sm2O3 beyond 0.02 M fraction. The overall refractive index of the glass system decreases along with the decrement in polarizability and optical basicity. The synthesized glass samples possess metallization criterion values of 0.30399 to 0.31068 which indicates that the glasses can be used for non-linear applications. The nonlinear behaviour of the fabricated samples which include the nonlinear absorption coefficient, nonlinear refractive index, and third order susceptibility attributed to changes in the glass structure. Silica borotellurite glass doped with 0.05 M fraction of samarium ox

Effect of heat treatment on optical, elastic and thermal properties of silica borotellurite glass doped with manganese

The properties and applications of various glass materials have been improving in daily life. Rice husk is the major source of biomass waste and offer an immense potential to create bioenergy. Rice husk have been used as a source of silica in this research. In order to unveil the effect of heat treatment and manganese on physical, structural, optical, elastic and thermal properties of silica borotellurite glass system, the quaternary glass system {[(TeO2)0.7(B2O3)0.3]0.8(SiO2)0.2}1-x(MnO2)x where x = 0.00, 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction were successfully fabricated through melt quenching technique. The physical, structural, optical, elastic, and thermal properties of the glass samples were investigated by using densimeter, X-ray Diffraction (XRD) spectrometer, Fourier Transform Infrared Spectrometer (FTIR), ultrasound technique and UV-Visible Spectrophotometer (UV-VIS) as well as Differential Scanning Calorimetry (DSC). The samples underwent heat treatment process at temperature of 250 ℃, 350 ℃, 450 ℃ and 600 ℃ for 3 hours. The density of the glass is found to decrease for samples before and after heat treatment as more dopant were added into the glass system which suggest the substitution of a heavier element in the glass system by a lighter dopant. Meanwhile, the molar volume of fabricated glass increases as the concentration of manganese increase due to the growth of free volume in the glass network. The minimum and maximum values for molar volume are 2.823 x 10-5 and 3.141 x 10-5 m3/mol respectively. Structural unit of TeO4, TeO3, BO4 and BO3 were detected in samples before and after heat treatment procedure while Mn structural unit was only found in samples after heat treatment process at 600 ℃. The detection of Mn structural unit indicates that heat treatment procedure causes the glass network start to restructure. The amorphous and crystalline nature of the glass is confirmed by using XRD analysis. SEM images show the agglomeration of the particle after heat treatment process. In terms of optical band gap, refractive index, and Urbach energy, all of the samples possess the same trends as well as some variations in the values as more dopants are added into silica borotellurite glass system. The inconsistent values as well as trends for the investigated parameter suggest that the formation of bridging and non-bridging oxygen take place in the glass system. The largest value of refractive index is 3.57 while the smallest Urbach energy value among all the synthesized samples is 0.39 eV. The current value of refractive index in the market is 1.98. The small Urbach energy hints the less disorderness in the glass structure. On the other hand, the elastic moduli and other elastic parameters of the prepared glass samples are found to be inconsistent with the addition of more manganese element in the silica borotellurite glass system. The decreasing trends in the ultrasonic velocities have contributed to the decrement in rigidity and compactness of the glass system. The value of Poisson’s ratio indicated that the glass sample have high cross-link density since the values lie on the range 0.1 to 0.2 for glass samples before and after heat treatment glass samples. Furthermore, the thermal properties of the glasses show that the glass sample have increasing thermal stability and glass transition temperature with the introduction of manganese in the silica borotellurite glass system. The increment in both thermal stability as well as glass transition temperature after the addition of manganese proved that the introduces dopant increased the rigidity and the stiffness of the bond in the glass network. The prepared glass samples can be categorized as strong glass former since the fragility index for samples before and after heat treatment lies in the range of 0.84 to 0.90. In conclusion, the addition of manganese and the heat treatment process done on the silica borotellurite glass have altered the properties of the glasses in different ways. This research is able to provide new knowledge regarding transition metal doped silica borotellurite glass and effect of heat treatment on the glass system. The results from the refractive index suggests that silica borotellurite glass doped with manganese have potential to be used as UV absorbance glass

Techno-socio-economic analysis of fog-to-water solution for climate change hazard area:Sumba Island, Indonesia

The global demand for water has been growing rapidly in the last decade with a global population growth rate of 1.1% p.a., which is equivalent to 81 million people per year. Southeast Asian countries are facing severe water scarcity challenge due to their location in the tropics. In 2018, the Sumba Island experienced the highest temperature of 36°C and lesser rainfall of 911.1 mm3 per year and it was classified as a long dry island prone to drought due to dry winds from Australian desserts. This paper focuses on the perceived effect of water scarcity on livelihoods in the Mandahu Village, Indonesia, due to climate change. Sampling and survey covered rural households and the findings showed that the average household of 4 to 8 people consumed around 250 dm3 of water per day. The community relied on two main sources of clean water from two main springs. However, the prolonged dry season from May until December every year results in major challenges to access water and eventually affect the agricultural productivity. Hence, the feasibility of the fog collection technology has been investigated from technological, economic and social points of view as a reliable and cost-effective source of water. The outcome of this work will produce a feasibility statement for fog-to-water as an alternative solution counteracting water scarcity in the Sumba Island, a solution which can be replicated in other climate change stricken hot spots in Southeast Asia