Lithium Borate Glasses Research Articles

Optical Properties of Lithium Borate Glass Containing Barite

Through this research we have prepared samples of glass, which includes 60 mol%B2O3 – x mol %barite – (40-x) mol %Li2O, where x= 5, 7.5, 10, and 15 mol%. The samples fabricated by the melt quenching technique. The samples are melted in alumina crucible at 1473 K for 1.5 h in an electric muffle furnace (LENTON). The glasses were casted into stainless molds, and then immediately transferred to an annealing furnance at about 400°C. The aim of this work is to determine the extent of the effect of raw barite on the physical and optical properties of this glass. The optical transmittance and reflectance spectrum of the glasses in this work were determined in the wavelength range 300–2500 nm at room temperature. The physical and optical properties of the following prepared glass samples have been determined and calculated (density, volume molar, refraction index, Optical dielectric constant, molar refractivity and electronic polarizability) for glasses prepared.

Investigation of TL dosimetric parameters of lithium borate glass doped with dysprosium

Abstract The current work presents a study of the thermoluminescence (TL) properties of glow curves obtained from lithium borate glass samples doped with different concentrations of dysprosium (Dy). The first part of the study is aimed to analyse the TL glow curves, obtained from the glass samples irradiated with beta-particles, to determine the number of composing TL peaks and to extract the kinetic parameters of the samples using different methods. The second part is dedicated to characterizing the TL dosimetric properties of the individual TL peaks composing the recorded TL glow curves. The analysis has shown that the glow curves corresponding to the glass samples doped with different concentrations of Dy compose of five overlapping TL peaks with trap depths ranging from 0.733 to 1.289 eV. The kinetic parameters obtained from the different methods agree to good accuracy.

Ravishing blue emission from Ce3+ activated lithium borate glasses for photonic applications

Lithium borate glasses activated with specific concentrations of Ce3+ ions have been processed by melt quenching technique. X-ray diffraction and SEM with EDAX carried out structural and surface morphology with elemental confirmation respectively. The nebulous nature of glassy matrices have been affirmatively confirmed by XRD and it was corroborated with SEM analysis. A distinguished absorption band is noticed in the ultraviolet region and the photoluminescence spectra displays a broad and intense blue emission band in the region from 395 nm to 570 nm which is centered at 447 nm (5d→4f) by exciting with 350 nm in Ce3+: LBZ glassy matrices. The dazzling blue emission intensity was significantly ameliorated by improving the addition of Ce3+ ion concentration in the glass matrix. The blue emission intensity has been found to be decreased at higher concentrations due to concentration quenching and the optimal concentration of Ce3+ ions is estimated to be 0.5 mol%. The fluorescence decay time has been evaluated as 0.86 ms from the decay profile of 0.5 mol% Ce3+: LBZ glass. Chromaticity coordinates were determined from the luminescence spectra, which are found to be falls in the bright blue region. The obtained blue emission CIE coordinates are close to standard EBU and NTSC coordinates for blue illumination. In view of these spectral features, 0.5 mol% Ce3+: LBZ glass could be recommended as promising candidate for the applications of blue emissive photonic devices.

Mixed-Alkali Effect in Borate Glasses: Thermal, Elastic, and Vibrational Properties

When oxide glasses are modified by dissimilar alkali ions, a maximum in the electric resistivity or the expansion coefficient appears, called the mixed-alkali effect (MAE). This paper reviews the MAE on the thermal, elastic, and vibrational properties of the mixed-cesium lithium borate glasses, x{(1−y)Cs2O-yLi2O}-(1−x)B2O3. For the single-alkali borate glasses, xM2O(1−x)-B2O3 (M = Li, Na, K, Rb, and Cs), the glass transition temperature, Tg = 270 °C, of a borate glass monotonically increases as the alkali content x increases. However, for the mixed-cesium lithium borate glasses the Tg shows the minimum against the lithium fraction y. The dependences of the elastic properties on the lithium fraction y were discussed regarding the longitudinal modulus, Poisson’s ratio, and Cauchy-type relation. The internal vibrational bands related to the boron-oxide structural groups and the splitting of a boson peak were discussed based on Raman scattering spectroscopy. The MAE on various physical properties are discussed on the basis of the changes in the coordination number of the borons and the nonbridging oxygens caused by the dissimilar alkali ions.

Influence of Bi2O3/WO3 substitution on the optical, mechanical, chemical durability and gamma ray shielding properties of lithium-borate glasses

Six different lithium bismuth boro-tungstate glasses with chemical composition 20Li2O-(20-x)Bi2O3-xWO3-60B2O3 (x = 0, 1, 2, 3, 4 and 5 mol%) were produced by the quenching method. Then, the glasses were investigated by means of their optical, mechanical, chemical durability and gamma ray shielding properties. Measured values of density and ultrasonic velocities were used to determine the elastic properties of the glasses. The optical band gap determined using the absorbance spectrum fitting (ASF) model was found to decrease under Bi2O3/WO3 substitution. The presence of BO3, BO4, BiO6, and WO4 structural groups in the glasses was confirmed by Fourier transform infrared spectroscopy (FTIR). The dissolution rate in the glass 20Li2O–15Bi2O3–5WO3–60B2O3 (LBWB5) was found to be 10 times lower than 20Li2O-20Bi2O3– 60B2O3. Mass attenuation coefficients (MAC) values of the produced glasses were determined using the MCNPX Monte Carlo code and Phy-X/PSD program. The photon attenuation parameters such as half value layer (HVL), mean free path (MFP), effective atomic number (Zeff), exposure buildup factor (EBF) and energy absorption buildup factor (EABF) were also studied. The obtained results showed that Bi2O3/WO3 substitution has a direct impact on the photon attenuation abilities of produced glasses. More specifically, HVL values increased from 0.252 × 10−2 cm for LBWB0 glass to 0.275 × 10−2 cm for LBWB5 glass. However, different trends were observed for the photon buildup factors for the produced glasses. It can be concluded that the produced glasses have promising structural, optical, and photon attenuation properties to be used for gamma shielding applications.

Blue, Red, and Green Emission from Chromium and Copper Metal Doped Lithium Borate Glass

The influence of copper metal on the structural and optical properties (absorption and emission) of the lithium borate glass samples containing chromium considered. The analysis of FTIR spectra measured, indicated the copper and chromium ions act as network former and modifier depend on the concentration of everyone in the sample content. The ratio between the BO4 groups to the total boron groups (BO4+BO3) decreases with the copper content increases up to 2 mol % and then increase. The optical properties that the Dq/B decreases with the increase the copper and higher than 2.3 which indicates the glass samples containing Cr3+ions in the high-field sites and produce conventional laser action. The emission spectra show the intensity emission bands at 440 nm, 540 nm, and 730 nm for relative strong blue, green and red bands respectively.

Spectroscopic properties of lithium borate glass containing Sm<sup>3+</sup> and Nd<sup>3+</sup> ions

<p><span>Lithium borate glass samples mixed with a different concentration of Sm<sup>3</sup>+ and Nd<sup>3+</sup> ions organized by quenching technique. Structural, vibration groups and spectral properties of glass samples investigated using X-ray diffraction, FTIR, UV/Vis/NIR and photoluminescence spectroscopy. The X-ray confirmed the lithium borate glass samples containing Sm<sup>3+</sup> and Nd<sup>3+</sup> ions in the amorphous state. Luminescence spectra of glass samples excited at 400 nm recorded, here three luminescence bands observed in Visible region, which due to spectra materials (Sm3+, Nd3+). These indicate that these glass samples responsible orange emission and used in the improvement of materials for LED, and optical devices. The functional vibration groups of the glass matrix studied using FTIR spectroscopy.</span></p>

Dosimetric properties of lithium borate glass doped with dysprosium.

Characterization of thermoluminescence (TL) properties of lithium borate glass samples doped with different concentrations of dysprosium (Dy) was carried out. Samples were prepared using a melting method at 1100°C and irradiated with β-particles. The glass samples doped with 0.1% Dy displayed the best TL dosimetric properties compared with other compositions. Deconvoluted analyses of the glow curves displayed five overlapping TL glow peaks located between 392.0 and 510.3 K. A good linear TL dose-response for β-particles was obtained in the dose range 66.6 mGy to 33.3 Gy. The minimum detectible dose was evaluated to be 205.4 μGy and samples revealed thermal fading in 312 h to 29% of their original value.

A study on optical, spectroscopic and structural properties of copper-doped calcium lithium borate glasses

In this work, the physical properties of calcium lithium borate glasses are investigated upon the inclusion of Cu+2 ion dopant. UV–Vis–NIR, photoluminescence, FTIR, and XRD techniques were, respectively, used in this study. From the optical absorption response of the samples, direct and indirect energy band gaps were calculated and they were found to be in the ranges of 3.57–3.28 eV and 3.78–3.6 eV, respectively. Results showed that the refractive index was increased from 2.258 to 2.326 with the increase in Cu2O concentration. Also, three main emission bands were observed in the luminescence spectra at around 399, 483, and 575 nm, which are correlated with the change in the copper concentration. Results of the FTIR spectroscopy showed various peaks in the ranges of 1383–1415 cm−1 and 1062–1076 cm−1, which can be attributed to the trigonal and tetrahedral stretching vibrations of BO3 and BO4 units.

Physical and Fourier Transform Infrared Studies of ZnO‐Al2O3‐Li2O‐B2O3 Glass System Incorporated with Cu2+ and Mn3+ Ions

AbstractZinc Alumino Lithium borate (ZnAlLiB) glasses of different compositions doped with Cu2+ and Mn3+ ions have been prepared using a conventional melt quenching technique. Fourier transform infrared (FT‐IR) studies have been carried out for ZnAlLiB glasses. The physical properties have been measured. The FT‐IR studies indicate that insertion of Cu2+ ions produces [BO3] and [BO4] basic structural units by breaking the boroxol (B3O6) ring, while manganese ions are found to gradually depolymerize MnO2─B2O3 glass matrix. This report presents the synthesis and FT‐IR studies of zinc alumino lithium borate glasses doped with CuO and MnO2. The local structure of copper and manganese ions in the glass system can be studied.

Iron (III) oxide doped lithium borate glasses: structural and charged particles/photon shielding properties

The elemental composition and surface morphologies of the (Li2B4O7) (100-x) - (Hematite) x glass samples (here x = 10,20, 30 and 40% weight) were acquired by SEM/EDX measurements. Using the EDX results, the mass attenuation coefficient (µ/ρ in units of cm2/g) of the glasses were generated with MCNPX simulation codes and calculated by XCOM software. Both results were matched by utilizing relative deviations. Next, Half Value Layer (HVL), Effective Atomic Number (Zeff), Mean Free Path (MFP), Exposure Buildup Factors (EBF), Energy Absorption Buildup Factors (EABF), Fast Neutron Removal Cross Sections (ΣR) and Relative Dose Distribution (RDD - for gamma and neutron) were calculated. Mass Stopping Power (MSP) and Projected Range (PR) values were calculated to examine the proton and alpha shielding properties of the hematite doped glass samples. According to the results obtained, µ/ρ, Zeff, and ΣR values increase as the percentage of hematite mineral in the glass samples increases. In addition, it was observed that HVL, MFP, EBF, EABF and RDD values decreased with increasing hematite percentage. The increase in the rate of hematite in the glass provided alpha and proton particles to have shorter ranges. Among the studied glass samples, lithium borate glass with 40% hematite mineral ratio is the sample with the best gamma, neutron and charged particles shielding features.

Structure Dependence of Poisson's Ratio in Cesium Silicate and Borate Glasses.

In glass materials, Poisson’s ratio (ν) has been proposed to be correlated with a variety of features, including atomic packing density (Cg), liquid fragility (m), and network connectivity. To further investigate these correlations in oxide glasses, here, we study cesium borate and cesium silicate glasses with varying modifier/former ratio given the difference in network former coordination and because cesium results in relatively high ν compared to the smaller alkali modifiers. Within the binary glass series, we find positive correlations between ν on one hand and m and Cg on the other hand. The network former is found to greatly influence the correlation between ν and the number of bridging oxygens (nBO), with a negative correlation for silicate glasses and positive correlation for borate glasses. An analysis based on topological constraint theory shows that this difference cannot be explained by the effect of superstructural units on the network connectivity in lithium borate glasses. Considering a wider range of oxide glasses from the literature, we find that ν generally decreases with increasing network connectivity, but with notable exceptions for heavy alkali borate glasses and calcium alumino tectosilicate glasses.

Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and nuclear radiation shielding properties of [α-Fe3+O(OH)]-doped lithium borate glasses

Goethite [α-Fe3+O(OH)]-doped lithium borate glasses in the chemical form of [(100 − x) Li2B4O7 mineral x = 10, 20, 30, 40 wt%] were synthesized and investigated in terms of their ability to protect the human being and environment from ionizing radiation. Elemental analysis of four different goethite [α-Fe3+O(OH)]-doped lithium borate glass samples called GOG10, GOG20, GOG30 and GOG40 prepared in different contribution rates was tested using energy-dispersive X-ray technique. In addition, the surface morphology of the manufactured glass samples was determined by scanning electron microscopy. The glass samples subject to the study were evaluated in terms of radiation shielding properties by calculating the shielding parameters such as mass attenuation coefficient (μm), half value layer, mean free path, effective atomic number (Zeff), exposure and energy absorption build-up factors, effective removal cross section (ΣR) for fast neutron and RDD (for gamma and neutron) with the help of the XCOM and MCNPX simulation code. Mass stopping power and projected ranges values of the studied glass samples were calculated in order to consider the shielding performance against proton and alpha particles. The results showed that increase in goethite additive increases the gamma protection capacity of glasses. As a result, the glass sample with the highest goethite contribution encoded with GOG40 has better shielding efficiency in terms of the gamma and neutron radiation shielding.

Radiation attenuation and optical features of lithium borate glasses containing barium: B2O3.Li2O.BaO

The influence of BaO on the optical characteristics and nuclear radiation shielding properties for 60B2O3-(40-x)Li2O-xBaO: x = 0, 5, 10, 15, and 20 mol% glasses was investigated. Various optical parameters such as optical transmission and reflection loss (TOptical, RLoss), molar refraction and molar polarizability (RMolar, αMolar), optical and static dielectric coefficients and metallization criterion (εOptical, εStatic, MCriterion), and metallization property according to refractive index and optical energy gap (M(nLinear), M(EOptical)), were determined. The results confirmed that RMolar changes directly with αMolar, while TOptical changes inversely with RLoss. The mass attenuation coefficient (μ/ρ) was investigated using WinXCOM software and the results showed that all the S1–S5 glasses have good attenuation ability at 284 keV due to their high mass attenuation coefficients (μ/ρ). The highest and lowest values of μ/ρ occurred at 284 keV and 1.33 MeV respectively and varied between 0.1055 and 0.1361 cm2/g and 0.0526–0.0534 cm2/g. The linear attenuation coefficient (μ) increased with the gradual addition of BaO from glass S1→S5. The results showed that the effective atomic number (Zeff) for S1 is almost constant, while S5 possessed the highest Zeff values. The half value layer (HVL) was estimated and the effect of BaO on this parameter was analyzed. At 284 keV, the HVL values were 2.8192, 2.3847, 2.1597, 1.9687 and 1.8936 cm for S1–S5 glasses respectively. The S5 sample possessed the least HVL, and accordingly, had better attenuation capabilities than the S1–S4 samples. Therefore, lithium borate glasses with high concentration of BaO can be applied in several optical and medical applications.

Gamma ray shielding capacity and build up factors of CdO doped lithium borate glasses: theoretical and simulation study

The ability of six cadmium doped alkali borate glasses was evaluated to be used for shielding application. Monte Carlo simulation code (MCNP-5) used to simulate the shielding parameters for gamma ray in energy zone increase from 0.015 to 15 MeV. The mass attenuation coefficient (MAC) of the studied glasses was found to enhance with replacement of Li2O with CdO contents. The higher MAC was found to increase from 1.652 to 7.453 cm2.g-1 for glasses BLNC0 without CdO content and BLNC10 with Coda 10 mol%. Moreover, the thicker half value layer was found to vary decrease from 18.201 to 12.144 cm and the higher mean free path was found to decrease from 26.259 to 17.521 cm for glasses BLNC0 and BLNC10 respectively. The effective atomic number (Zeff) for the investigated glasses was also estimated theoretically and the results showed enhancement of the Zeffwith insertion of CdO contents. The exposure buildup factors (EBF and EABF) were also calculated in the energy range between 0.015 and 15 MeV. Other pivotal, the removal cross section (ΣR) for fast neutron was also calculated for the investigated glasses. The obtained results showed a significant variation in the ΣR with the increase of CdO contents in the studied glasses.

Optical, structural and gamma ray shielding properties of dolomite doped lithium borate glasses for radiation shielding applications

The elemental analysis of dolomite [CaMg(CO3)] doped glasses encoded DG10, DG20, DG30 and DG40 with different compositions is tested using Energy Dispersive X-ray (EDX) technique. Next, the surface morphology of fabricated glasses was investigated with scanning electron microscopy (SEM). On the other hand, the optical properties of fabricated the Dolomite additive were evaluated along the wavelength ranged from 300 to 900 nm. At last, nuclear radiation shielding properties of dolomite glasses were determined for gamma-rays. It is observed from the optical absorption spectra that the surface becomes smooth with no agglomerations with Dolomite%30 and %40. In addition, the results showed that Dolomite additive improves the gamma protecting capacity of lithium borate glasses. As a result, it can be referred that a glass sample with the highest Dolomite additive encoded DG40 has better shielding efficiency in terms of radiation shielding.

Influence of alkaline earths on EPR spectra of lithium borate glasses doped with Fe (III) ions

Lithium borate glasses containing Fe (III) transition metal ion having composition 15RO-25Li2O-59B2O3-1Fe2O3 (where R= CaO, SrO and BaO) are synthesized via melt quench route. These glasses were characterized using X-ray diffraction (XRD). Electron paramagnetic resonance spectra of prepared glasses have been studied. The recorded spectra mainly consists of an intense resonance signals at g ∼ 4.282 and also at g ∼ 2.0032 along with a shoulder in the region of g ∼ 8.033 which is a characteristic of iron ions in the (3+) valence state in all the studied glasses. The number of spins participating in resonance (N) and its paramagnetic susceptibilities (χ) have also been evaluated. The spin concentration and the paramagnetic susceptibility at g = 2.0032 and at g = 4.282 increase by the substitution of alkaline earths from CaO to BaO respectively. The peak-to-peak line width ΔB for the resonance lines at g ≈ 4.282 and at g ≈ 2.0032 and the line intensity of the resonance centered at g ≈ 4.282 and at g ≈ 2.0032 have been evaluated. This EPR spectra has been analyzed in the light of different oxidation states of iron ions in order to understand the influence of alkaline earths as modifier oxide on the structure of glass matrix.

Morphological characteristics of nanoholes induced by single-shot femtosecond laser ablation of borates and aluminate silicates

Single-shot femtosecond laser ablation experiments with linearly and circularly polarized light were conducted in order to investigate the morphological characteristics of surface nanostructures in lithium borate crystals and glasses, a strontium borate crystal, lanthanide containing borate crystals, and aluminate silicate crystals: Li2B4O7 (LTB) and LiB3O5 (LBO) crystals and Li2O⋅2B2O3 (LTB) and Li2O⋅3B2O3 (LBO) glasses; SrB4O7 (SBO) crystal; Li6Gd(BO3)3 (LGB) and LaSc3(BO3)4 (LSB) crystals; and Ca2Al2SiO7 (CAS) and CaSrAl2SiO7 (CSAS) crystals. In the present study, the material and laser polarization dependance of the morphology of nanoholes was examined in these crystals and glasses. A single nanohole or two holes (a primary hole and a secondary hole) were observed in the borate and aluminate silicate crystals. The size of the nanohole is not restricted by the diffraction limit but instead is dependent on the laser fluence and the materials. It is suggested that the formation of these secondary nanoholes in the studied crystals is attributed to a spontaneous reshaping of the incoming Gaussian pulse into a Gaussian–Bessel pulse. In the LTB and LBO crystals, nanoholes (both primary and secondary holes) with subwavelength sides exhibit a quadrilateral (approximately square or rectangular) morphology, regardless of linear or circular polarization. The sides of the quadrilateral nanoholes lie approximately in the {h h 0} planes on the LTB crystal and in the ({h 0 0} and {0 0 l}) planes on the LBO crystal. We found that the nanohole morphology did not reflect the spatial distribution of the laser intensity. These phenomena were the first observations on the anisotropic morphology of nanoholes. These morphologies do not correspond to the circular symmetric pattern of the Gaussian intensity distribution of the incoming laser beam. This is contrary to the expectations based on the generally accepted laser ablation mechanism. The quadrilateral nanoholes could be an inherent morphology in the LTB and LBO crystals. The morphology of the quadrilateral holes in the LTB and LBO crystals is considered to reflect the continuous BO33− and/or BO45− network structure in their respective tetragonal or orthorhombic unit cells, in which self-tapped excitons are formed in an initial process under multiphoton excitation. In contrast, the SBO, LGB, LSB, CAS, and CSAS crystals and the LTB and LBO glasses exhibit circular nanoholes with subwavelength diameters independent of the laser polarization, the structure, or the composition. The isotropic morphology of nanoholes in these samples reflects the circular pattern of the Gaussian intensity profile of the focused laser beam.

Structural, mechanical and radiation shielding properties of newly developed tungsten lithium borate glasses: An experimental study

The melt quench technique was used to fabricate the (25-x)Li2O-75B2O3-xWO3 (x = 1, 3, 5 and 7.5 mol%). The mass attenuation coefficients (μm) of the studied glasses were obtained by using the Gamma (γ) rays spectrometer (CANBERRA photo multiplier tube base model 802) which includes a detector (3 × 3 in.) NaI(Tl) crystal and the multichannel analyzer. The measured values have been compared with XCOM program at selected photon energies. Geometric progression (G–P) fitting method has been used to calculate the exposure build-up factor (EBF) and energy absorption build-up factor (EABF) in the energy range of 0.015–15 MeV. Moreover, EBF and EABF values have been applied to compute the specific fraction of absorbed energy (Sfae) and relative dose distribution (Rdd). The pulse-echo technique has been used to measure the elastic moduli for glass samples. The TBL4 glass sample shows the highest μm, effective atomic number (Zeff) and Young moduli values and lowest half value layer (HVL), mean free path (MFP), EBF, EABF, Sfae and Rdd values. The results of this investigations revealed that the fabricated TBL4 glass sample could be potentially utilized as an efficient and desirable kind of glass material as gamma shield to reduce the deleterious effects of radiation.

JUDD-OFELT ANALYSIS OF Tb3+ AND UPCONVERSION STUDY IN Yb3+–Tb3+ CO-DOPED CALIBO GLASSES

We report on the study of the spectroscopic properties in Ytterbium-Terbium (Yb3+-Tb3+) co-doped calcium lithium borate (CaLiBO) glasses, with the study’s focus being on the upconversion process. Intensity parameters Ωλ for CaLiBO:Tb3+ are determined by the Judd-Ofelt method to be Ω2 = 15.5 × 10-20 cm2, Ω4 = 1.90 × 10-20 cm2 and Ω6 = 3.69 × 10-20 cm2. We have also obtained electric-dipole (and magnetic-dipole) radiative transition probabilities, branching ratios, and lifetime for the Tb3+:5D4 and 5D3 levels. In addition, an evaluation of the upconversion processes by luminescence and time-resolved spectroscopy were carried out. The upconversion rise and decay times, energy transfer probability from Yb3+ to Tb3+ ions, and the efficiency of the processes that depopulate the Tb3+:5D4 level after resonantly pumping the Yb3+:2F5/2 level were estimated. Our results showed that a cooperative energy transfer (CET) from two Yb3+ ions to one Tb3+ ion is the origin of the Tb3+ upconversion luminescence in the visible region. While, CET followed of the cross relaxation or/and excited state absorption is responsible for the upconversion luminescence in the ultraviolet region.