Series Of Glasses Research Articles

X-ray absorption spectroscopic studies of Fe environments in borosilicate waste glasses synthesized under a variety of redox conditions

Fe K-edge X-ray absorption spectroscopy (XAS) was performed on two borosilicate waste glass series to determine Fe valence and coordination changes over a wide range of redox synthesis conditions. Data were also collected on eight Fe-silicate standards, including the rare phase, pellyite, that was used as a tetrahedral Fe2+O4 standard. X-ray absorption near-edge structure (XANES) linear combination fits of the Fe2+O4, Fe2+O5, and Fe3+O4 standards data to the glass spectra determined Fe2+/Fetotal ratios from 0.07 to 0.90 that are within 10 % of Mössbauer findings. As the glasses become reduced, XANES indicates Fe3+O4 tetrahedra are being replaced by Fe2+O4 tetrahedra, and possibly, Fe2+O5 sites, while extended X-ray absorption fine structure analyses show average Fe-O distances increase from 1.88 to 1.96 Å. The XANES-determined three Fe-site population distributions in the glasses are similar to findings reported in a recent molecular dynamics study of Fe redox effects in waste glass.

Evidence for new fluoride coordination in SiO2-Al2O3-P2O5-CaO/SrO-CaF2 compositions used in ion-leachable ionomer-type cements: A 19F MAS-NMR investigation

Glass ionomer-type glasses are widely utilized in industrial and biomaterial applications due to their unique combination of biocompatibility, strong adhesive properties, and controlled ion release. The structural understanding of fluoride ions in these materials is critical for optimizing their performance and tailoring their properties to specific applications. In this study, we employ solid-state 19F magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy as a powerful tool to investigate the fluoride coordination environments in glass-ionomer-type glasses. A series of strontium-substituted glasses in the system SiO2-Al2O3-P2O5-CaO/SrO-CaF2 were synthesised by the high-temperature melt-quench technique and analysed by 19F MAS-NMR spectroscopy. A previously unknown F coordination environment with Sr was discovered.

Tunable emission and energy transfer of B2O3–Bi2O3–AlF3 glass system doped with Eu3+/Dy3+

The structure and luminescent properties of the B2O3–Bi2O–AlF3 glass system doped with Eu3+/Dy3+ ions in different molar ratios were studied. A series of glasses were synthesized by the conventional melt quenching technique. Glass transition and crystallization temperatures were examined by Differential Thermal Analysis (DTA) measurements. The amorphous character of the prepared samples was confirmed by the X-ray diffraction (XRD) method. Raman and FTIR spectra were collected and deconvoluted to investigate the glass micro-structure. Luminescence spectra revealed that the added rare-earth ions can be excited by a single wavelength. The emitted color can be tuned by changing the ratios of the Eu3+/Dy3+ ions and the excitation wavelength. Furthermore, the influence of the addition of AlF3 on the luminescence and decay times was investigated. In the glasses with 10 mol% AlF3 an enhancement of the emission and excitation spectra was detected. The energy transfer analysis confirms the energy transfer between Eu3+ and Dy3+ ions in the glass matrix. Additionally, the results of this study indicate that the B2O3–Bi2O–AlF3 glasses doped with Eu3+ and Dy3+ can be used as a color tunable phosphor.

Dynamic light scattering study of the non-exponential α-relaxation in sodium germanate glass melts

Photon correlation spectroscopy is used to measure the dynamic structure factor in a series of network-forming sodium germanate glass melts at temperatures near but above the glass transition. In addition to the primary α-relaxation, a slower diffusive process is identified with the diffusion of mobile Na cations within the oxide network. Along with determination of the glass transition temperature and fragility index, the non-exponentiality of the α-relaxation is characterized and compared with previous studies in sodium phosphate and sodium borate melts. A key result found here is a temperature-dependent stretching exponent which uniformly approaches a universal value of β = 0.5 in all three oxide systems as the glass transition is approached.

Structural investigation and thermal properties of Al2O3-PbO-B2O3 glasses

Two series of aluminum lead borate glasses, (Al2O3)y(PbO)35-y(B2O3)65 and (Al2O3)y(PbO)70-y(B2O3)30, were prepared and effect of PbO → Al2O3 substitution on their structure and thermal properties was studied. The semi-quantitative analysis of the Raman spectroscopy data was used to structural interpretation of glass transition behavior in the Al2O3-doped lead borate glasses. The mechanisms of structural reorganization of glassy network under PbO → Al2O3 substitution were found to differ for the studied series although Al3+ ions are incorporated in the glass network, mainly, in form of AlO4 units in the both cases. The formation of AlO4 tetrahedra is accompanied by transformation of various isolated borate anions into finite-sized metaborate chains as well as the conversion of four-fold coordinated [BØ3O−]− species with one non-bridging oxygen atom into fully polymerized [BØ4]− tetrahedra in the (Al2O3)y(PbO)70-y(B2O3)30 glasses. In the series of glasses with high concentration of B2O3, B[4] → B[3] transformation including the shift of [BØ4]− ↔ BØ2O− equilibrium toward the right side is the main process of structural reorganization caused by PbO → Al2O3 substitution. In this case, the change in the network connectivity is determined by competition between increasing the amount of Al-O-B bonds against the background of decreasing the amount of B-O-B bonds between borate structural species. In the B-poor series, the glass transition temperature increased with Al2O3 from 280 to 360 °C, and the crystallization peak onset occurs at 340 and 380 °C for the glasses with the 0 and 3 mol.% Al2O3 contents, respectively (higher aluminum oxide contents already prevent crystallization). In the B-rich series, Tg increases with the Al2O3 content from 430 to 490 °C, and the crystallization occurs at 560 °C only for the Al2O3-free glass. The structural relaxation behavior in the glass transition rage was described in terms of the Tool-Narayanaswamy-Moynihan model. The activation energy for the relaxation movements was found to be non-monotonous in case of both compositional series.

Rare-earth (Dy3+ and Pr3+) ratio variation effects on electrical properties of sodium fluoride alumino borate glass system

Inlaying two RE ions simultaneously in the glass network, greatly impacts its properties and therefore its study is paramount. A glass series with composition 60B2O3 + 30NaF + 10Al2O3 + (1 − x) Dy2O3 + (x/3)Pr6O11 (where x = 0, 0.2, 0.5, 0.7 and 1 mol%) was prepared by melt quenching technique. The influence of both composition, concentration of rare earth ions and temperature variation in wide frequency range on electrical properties were investigated. The DC and AC conductivity curves for all the prepared compositions obeyed Arrhenius relation and Jonscher’s Power law, respectively. The frequency exponent “s” parameter was obtained to study the conductivity mechanism. Dielectric parameters were observed to be decreasing with a rise in frequency and increasing with temperature. Electric Modulus and Nyquist Plots for all compositions were studied to examine the relaxation behavior in prepared glasses as Debye or non-Debye. Depressed semicircular Nyquist plots were observed.

Impacts of substituting magnesium with zinc on crystallization behaviors in an aluminosilicate glass.

A series of zinc-magnesium mixed aluminosilicate glasses with the molar composition (1-r)MgO·rZnO·Al2O3·2.5SiO2, where r = 0.00, 0.25, 0.50, 0.65, 0.75, and 1.00, were fabricated to probe the effects of substitution of magnesium with zinc on crystallization behaviors. Based on the evolution of phase compositions as revealed by calorimetric behaviors and X-ray diffraction patterns, a series of transparent surface crystallized glasses ranging from high transparency for the pure Zn-end member to heavy translucency for the pure Mg-end member were fabricated through heat treatment at the first crystallization peak temperature for 20 min. With the substitution of Mg with Zn, the evolution of morphology unveiled by optical microscopy is ascribed to the alteration of crystal phases formed from the sole metastable Zn-β quartz solid solution to the coexistence of polycrystal phases containing Zn-β quartz solid solution, μ-cordierite, or α-cordierite. These findings are very helpful for optimizing the performance of crystallized aluminosilicate glasses.

Effects of ionic cross-linking on the non-exponentiality of the [formula omitted]-relaxation in metaphosphate glass melts as measured by dynamic light scattering

Photon correlation spectroscopy was conducted on a series of metaphosphate glass melts to measure the liquid's dynamic structure factor near the glass transition and thereby characterize the degree of non-exponentiality in its time decay. Each metaphosphate consists of polymeric chains of [PO4]−1 monomers interspersed by a variety of modifying cations (Ag+, Ba2, Ca2+, Sr2+) which can potentially form inter-chain crosslinks via ionic bonding. Our results show that the non-exponentiality of the α-relaxation decreases monotonically with increasing field strength of the cation-oxygen bond.

Mixed alkaline earth effect on nanomechanical properties of glass

The mixed alkaline earth effect (MAEE) on the mechanical behavior of oxide glasses have received significant attention of glass scientists. In this study, we unveiled the MAEE on the nanomechanical properties of a boroaluminosilicate (BAS) glass series with the varying molar ratios of R=[MgO]/([MgO]+[CaO]), through a combination of nanoindentation, nanoscratch, and nanowear tests. The MAEE was observed as positive deviations from the linear trend in nanohardness and reduced modulus with varying R. On the contrary, the MAEE manifested as negative deviations from the linear trend in nanoscratch depth, nanoscratch residual depth, nanowear volume, and volume densified by nanowear. The maximum and minimum values were observed at R = 0.56. The MAEE on nanowear behavior was found to be mainly governed by the nano-indentation and subsurface densification. These discoveries provide valuable insights into the nanomechanical properties of glass surfaces, contributing to the development of advanced glasses with improved mechanical properties and extended lifespans.

Investigation of dysprosium oxide substitution on physical, electrical and dielectric properties in sodium borosilicate glass system

Dysprosium oxide doped sodium borosilicate glasses were prepared in this study using a usual melt-quenching process. Further XRD, FTIR, density measurements, electrical conductivity, and dielectric properties were utilized to explore the prepared glassy samples. We found that all produced samples exhibit amorphous nature through X-ray diffraction. Increase in density and molar volume were found when dysprosium oxide concentration increased, which was ascribed to dysprosium oxide's greater molecular weight. Density data was used to calculate and explain several physical characteristics, including rare earth ion concentration (N), polaron radius (rp), internuclear distance (ri), and field strength (F).

Concentration dependent cyan emission by europium‐doped borosilicate glasses

AbstractAt present, doping of different alkaline‐earth metal ions is mainly used to tune the emission peak of europium (Eu) ions in glasses. However, the optimization of Eu‐doped glasses is hindered due to limited discussion on the relationship between local glass network structure, concentration of Eu ion dopants, and visible light emission by Eu ions. In this study, we prepared two series of borosilicate glasses doped with Eu ions, by varying the ratio of SiO2 to B2O3 and adjusting the concentration of Eu ion dopants to obtain cyan emission. The optical properties, structure, and differential scanning calorimetry (DSC) of the investigated glasses were systematically studied. With gradual increase in the content of SiO2, red shifting from 471 nm to 492 nm was observed under excitation at 410 nm, with the introduction of Eu2O3 also causing a redshift from 471 nm to 488 nm. The spectral results also revealed that under excitation at 410 nm all the glass samples exhibited cyan emission, with the optimal cyan peak at 492 nm (Si‐45) and the strongest cyan emission at Eu‐0.4 (480 nm). By adjusting the concentration ratios of Si to B in europium‐doped borosilicate glass, it was observed that by altering the [SiO4] tetrahedra, [BO4] tetrahedra, and [BO3] triangles within the glass ultimately cyan emission can be achieved. By varying the doping concentration of Eu ion to change the degree of local Eu ion clustering in the glass system, cyan emission can be achieved by tuning the emission peak.

The role of Nb2O5 on structural, mechanical, and gamma-ray shielding characteristics of lithium molybdenum borate glasses

A series of glasses with the formula 64B2O3–16MoO3- (20-x) Li2O- xNb2O5 where x = 0 to 12, were synthesized. Utilizing XRD profiles, the amorphous state of the investigated glasses has been established. With an increase in Nb2O5 it is found that the gradual replacement of Li2O by Nb2O5 increases the density from 2.43 to 3.09 g/cm3 and the molar volume of the studied glasses decreases from 30.27 × 10−6 m3 mol−1 to 24.91 × 10−6 m3 mol−1. The addition of Nb2O5 increases the number of bridge oxygens and alters the coordination number of the glasses by forming BO4 structural units, according to the FTIR results. As the Nb2O5 increased ultrasonic velocities VL&VT also increased. VL increased from 4780 to 5150, and VT increased from 2295 to 2715 m/s. Ultrasonic velocity and elastic moduli increase as a result of structural changes brought on by an increase in BO4 at the expense of BO3. It is noted that the theoretically predicted elastic moduli utilizing Makishima-Mackenzie models (MMM) and the experimental elastic moduli indicate a very good agreement. The features of gamma-ray shielding were evaluated using the Phy-X/PSD program. It has been noted that the greatest mass & linear attenuation coefficient (MAC) & (LAC) occurred at 0.02 MeV. With an increase in energy, the half- and tenth-value layers HVL and TVL increased, while decreasing with an increase in Nb2O5. These observations suggest that the synthesized glasses are better candidates for gamma radiation shielding.

Influence of B2O3/ZnO Exchange in Gamma Shielding Properties of TBTZ Glasses

A series of tellurite glass having compositions: 60 TeO2 – (30-x) B2O3 – 7 TiO2 – (3+x) ZnO where x = 0, 1, 2, 3, 4, and 5 mol% were successfully facbricated, i.e., by applying the melt-quenching method. Melting was carried out at 950˚C in 70 minutes. The density of all the investigated glasses were calculated using an empirical equation. The density of TBTZ increases from 4.005 to 4.197 g/cm3 with rising ZnO concentration. It can be understood that density enhancement is due to an improvement in glass molecular weight. Whereas, gamma shielding properties of the glasses was simulated using Phy-X/PSD software for photon energy in the range 0.005 – 15 MeV. Linear attenuation coefficient (LAC) and half-value layer (HVL) are obtained and discussed. It was shown that LAC increase and HVL decrease within all gamma photon energies within alteration of ZnO concentration. The increase and decreation vary and depend on gamma photon energy. Identify relevant articles in literature searches, great care should be taken in constructing both. (boro-tellurite glass, linear attenuation coefficients, Half Value Layer, Gamma Shielding, radiation shielding)

Spectroscopic and Lasing Properties of Highly Concentrated Glasses

A method has been advanced for the quantitative separation of the degradation channels of the electron-excitation energy of rare-earth activators, which is based on measurements of the duration of activator luminescence and of the absorption coefficient of OH-groups in concentration series of glasses. The optimal neodymium concentration has been established for obtaining the maximum gain in phosphate glasses. Preliminary lasing tests of the concentration series of phosphate and also silicate glass with a neodymium concentration of approximately 2.3 × 1020 ions cm–3 have been performed.

Physical and radiation shielding properties for borate, boro-tellurite, and tellurite glass system modified with different modifiers: Comparative study

Two newly synthesized glass series, 10Bi2O3-20BaO-(70-x)B2O3-xTeO2, and 10MoO3-20SrO-(70-x)B2O3-xTeO2, where x = 0, 35, and 70 mol%, were fabricated using the melt-quenching technique. The fabricated glass samples' physical properties and radiation shielding capabilities were examined. The insertion of TeO2 into the glass composition increased the density values, with the glass samples labeled BBB-T70 (6.53 g/cm3) and SBM-T70 (5.66 g/cm3) exhibiting the highest density due to the increased concentration of TeO2. The addition of TeO2 led to loosely bonded glasses, indicating lower glass stability. Using SRIM and Phy-X/PSD software, the radiation shielding capabilities of the produced samples were investigated for various radiation types, including alpha particles, protons, neutrons, and gamma rays. The increase in TeO2 content and the reduction in B2O3 revealed significant increases in the linear attenuation coefficient (LAC) values and improved gamma shielding properties. For example, the LAC values at 0.283 MeV are 0.283, 0.367, 0.667, 0.902, 1.095, 1.313, and 1.55315 cm−1 for SBM-T00, SBM-T35, SBM-T70, BBB-T00, BBB-T53, and BBB-T70, respectively. However, the SBM-T00 sample exhibited lower charged particle shielding properties. The SBT-T35 and BBB-T00 samples showed the highest ability to stop fast neutrons. In conclusion, the glass samples synthesized in this work are highly recommended for shielding against various ionizing radiation sources.

Mechanical, structural, and radiation shielding characteristics for transparent boro-tellurite glasses modified with strontium and bismuth oxide ratios

In this investigation, a new transparent boro-tellurite glass series modified with strontium oxide and differing ratios of bismuth oxide was synthesized to explore the radiation shielding ability. The mechanical and physical features were checked theoretically. At the same time, the structure for fabricated glasses was investigated by Raman spectra, thermo-gravimetric analysis (TGA), and X-ray diffraction (XRD). According to Raman spectra results, the prominent peaks displayed enhancing and shifting to lower wavenumber from 774 cm−1 for TBSB0 to 751 cm−1 for TBSB20 with adding Bi2O3 instead of TeO2. XRD proved the amorphous nature of all glass samples. In contrast, TGA explored the thermal stability by studying the weight loss for TBSB0 and TBSB20 that are 1.6264 % and 0.3198 % at 1000 °C, respectively. The inclusion of Bi2O3 as opposed to TeO2 resulted in a density enhancement from 4.3200 to 5.6900 g/cm3, packing density (Vt) from 0.4221 to 0.4715, and mass attenuation coefficient (μm, at 184 keV) from 0.2921 to 0.7185 cm2/g. On another side, experimental evaluation of the radiation shielding properties was conducted, and the μm values were compared with XCOM data. The theoretical and experimental relative difference was in the 0.445–5.974 % range. The direct relation between Bi2O3 concentrations and radiation shielding properties is obvious. TBSB20 sample showed the highest radiation shielding capacity compared with other fabricated glasses. These results indicate the ability to use the fabricated glasses in the radiation shielding field.

Influence of CaF2 on the spectroscopic studies of Dy–Eu co-doped fluoroborate glass for lighting applications

To investigate novel glass materials applicable to W-LED, we designed and prepared a series of glasses with varying compositions. The compositions of the glasses were (64-x)B2O3–15Al2O3–10Na2O–10Bi2O3-xCaF2-0.5Dy2O3-0.5Eu2O3 (x = 0, 5, 10, 15, 20, 25). The glasses were synthesized using the melting quenching method. The effect of CaF2 on the structural feature of fluoroborate glass was studied by infrared spectroscopy analyses. Determination of fluorine content in glass by 19F NMR inversion spectroscopy. The absorbance of glass increased as the CaF2 content increased in the visible and ultraviolet light ranges. The optical band gap of the prepared glasses was obtained from the absorption spectrum, which confirmed the existence of nonbridging oxygen (NBO) in the glass network structure. The fluorescence lifetime of the glass increases with increasing CaF2 content, and the quantum yield of the glass first increases and then decreases. In addition, fluoroborate glass had a lower Urbach energy, indicating that its network structure was relatively uniform and stable. In contrast, the increase in Urbach energy is due to the substitution of CaF2, leading to more defects. By adjusting the excitation wavelength and CaF2 content, the color temperature (1598–3346 K) and color rendering index (36–63) of fluoroborate glass can be effectively adjusted. These results show that the prepared Dy/Eu co-doped fluoroborate glasses have a potential application in white lighting.

The effect of borate on acellular bioactivity of novel mesoporous borosilicate bioactive glasses for tissue engineering

Four novel mesoporous borate-based 13–93 bioactive glass has been synthesized by a modified Stöber method. Thermogravimetric analysis, Inductively coupled plasma atomic emission spectroscopy, Fourier Transform Infrared Spectroscopy, X-Ray diffraction, Brunauer–Emmet–Teller and Barrett–Joyner–Halenda, nuclear magnetic resonance and Scanning Electron Microscope attached with Energy-dispersive X-ray spectroscopy analyses were carried out to investigate the physicochemical properties, in-vitro acellular bioactivity, and the degradation rate of the bioactive glasses in simulated body fluid across a range of times up to 21 days. The characterization data indicates that the bioactive glasses are amorphous and possess mesoporous properties. Likewise, an increase in boron content reduced the surface area and pore volume of the bioactive glass series. The observed decline is attributed to borate units' smaller atomic radius than silicate. The ability to deposit a new apatite layer in the bioactive glasses depends on the borate concentration. As such, an increase in boron content resulted in a decrease in apatite formation. Additionally, the studies showed that bioactive glasses made of borate degraded more quickly than their silicate counterpart. Overall, borate-based 13–93 bioactive glasses were effectively synthesized, and the in-vitro results showed potential usage for these bioactive glasses in tissue engineering situations where it is desirable to control bone growth or delay the onset of bioactivity.

Composition‐dependent leaching behavior in ion‐irradiated borosilicate glasses: A corrosion mechanism study

AbstractEvaluating the corrosion behavior of borosilicate glass after irradiation holds vital importance for the safe geological disposal of high‐level radioactive waste. This study examined the leaching properties of three kinds of sodium‐borosilicate (RNa2O‒B2O3‒KSiO2, denoted as “NBS”) glasses with the same R but varying K under 5 MeV Xe‐ion radiation to decipher the correlation between the corrosion mechanism and glass composition. After Xe‐ion radiation, an increase in [BO3] units was observed, indicative of the glass network depolymerization. Irradiated glasses exhibited a more significant change in [BO3] units over the leaching time compared to their pristine counterparts. There is a strong correlation between the initial dissolution rates of pristine glasses, the K value, and the proportion of Na. Additionally, the initial Si dissolution rate of the NBS glasses has been accelerated by heavy ion irradiation. For the same R value over the glass series, the initial Si dissolution rates in ternary borosilicate glasses change at similar rates after irradiation. This study concluded that the variation trend in the initial dissolution rate of Si and Na differs under ion radiation.

Ce3+-Yb3+, Tb3+-Yb3+ and Pr3+-Nd3+-Yb3+ mixed-doped TeO2–ZnO–Na2O glasses for enhancing the efficiency of silicon solar cells

In general, the sunlight wavelength absorbed by silicon solar cells is mainly concentrated in the range of 600–1100 nm. Although silicon solar cells can also absorb sunlight in the ultraviolet and visible regions with <600 nm, the utilization of light is very low. In addition, some high-energy photons in the ultraviolet and visible region can cause serious damage to silicon solar panels, reducing its useful lifetime and lowering its photoelectric conversion efficiency. Therefore, in order to make full use of the light in this range, we studied three-layer light-conversion glass doped with three groups of rare-earth ion to improve the utilization rate of light in silicon solar cells and prolong the lifetime. A series of zinc tellurate glasses (TeO2–ZnO–Na2O) doped with Ce3+-Yb3+, Tb3+-Yb3+ and Pr3+-Nd3+-Yb3+, respectively, were prepared by melting quenching method. The crystalline state and interior structure of the prepared glasses are characterized by using X-ray diffraction (XRD) spectra and Raman spectra. And the lowest phonon energy of these glasses is about 773 cm−2. The photoluminescence properties of rare-earth ions doped in these glasses are studied. The results show that the near infrared emission (centered at 980 nm) of activator ion (Yb3+) is observed when the sensitizer ions (Ce3+, Tb3+, Pr3+ and Nd3+) are excited by using 430 nm, 355 nm and 488 nm ultraviolet and visible (UV–vis) photons, respectively. The down-conversion and down-shift energy transfer mechanisms between sensitizer ion and activator ion are discussed. Based on the above research, a triple-layer zinc tellurate glass sample doped with Ce3+-Yb3+/Tb3+-Yb3+/Pr3+-Nd3+-Yb3+ in a certain ratio is prepared. And the current density-voltage (J-V) curves of silicon solar cell covered with triple-layer zinc tellurate glass were tested. According to the data obtained from J-V curves, the relative efficiency (Δη) of Si solar cells covered with Ce3+-Yb3+/Tb3+-Yb3+/Pr3+-Nd3+-Yb3+ triple-layer zinc tellurate glass is increased by 2.37% compared with that of silicon solar cell covered with blank glass. So, the above results can show that the glass has important application values in improving the energy efficiency of silicon solar cells.