Ternary Phosphate Glasses Research Articles

Study on temperature-sensitive factors relevant to thermographic features of Tb3+-doped phosphate glasses

Intensities of the 5D4 luminescence with the 5D3 level populated by GSA and ESA transitions of Tb3+ in ternary phosphate glass were measured at different temperature between 300 K and 675 K. Acquired 5D4 luminescence intensities related to GSA and ESA excitation transitions from thermally coupled 7F6 and 7F5 levels were treated to assess luminescence intensity ratios (LIR) as a function of temperature and resulting values of relative sensitivity SR. To understand origin of marked dissimilarity of SR values observed in some few Tb3+-doped hosts reported thus far an in-depth analysis of the excitation energy flow in systems under study is made. Spectra of absorption cross section and temperature dependent absorption coefficient for ESA transition were evaluated. Rates of temperature dependent cross relaxation process governing energy transfer between 5D3 and 5D4 were calculated. It was supposed that temperature-dependent absorption of colour centres in the blue region may affect adversely relative thermal sensitivity.

Radiation shielding features of Na2O–P2O5 glasses doped with MnO experimentally and using FLUKA and Phy-X

This research focused on examining the radiation shielding performance of (50% - x/2)P2O5-(50%-x/2)Na2O-xMnO (where x = 0, 5, 15, 25, and 33 mol%) glass system. The shielding review covered the radiation of photons, electrons, particles of heavy-charged, and neutrons. Hence, multiple parameters such as coefficient of mass attenuation (μm), transmission and buildup factors (HVL, MFP, EBF, and EABF), effective atomic number for samples (Zeff), and removal cross-section for fast neutron (FNRCS) of the selected samples were investigated. The results are determined experimentally and by employing FLUKA Monte Carlo software and Phy-X (ZeXTRA and PSD) theoretical programs. A relative discrepancy (RD) and a root-mean-square error (RMSE) were applied to verify the deviation between FLUKA and Phy-X values. An excellent agreement is noticed between measured, simulated, and calculated results. The research revealed that increasing MnO content improves the gamma, electron and heavy charged particle shielding efficiency of studied glasses. Although the addition of MnO has an insignificant impact on FNRCS (from 0.086 to 0.092 cm−1), obtained results identified the relationship between the packing density and shield ability against neutrons for ternary phosphate glasses. We found that the HVL values dropped from 13.898 cm to 11.568 cm at 15 MeV. A range of 7–12 for gamma, 8–12 for electron, 10–11 for proton, 10–11 for alpha, and 9–11 for carbon ion was the maximum value of Zeff that could be obtained. These glasses' shielding behaviors were contrasted with those of conventional materials. Accordingly, the sample with the highest mole fraction (x = 33 %) has higher shielding efficiency than ordinary concrete, Pyrex, and RS253-G18. Finally, the studied glass system can be a good compromise between highest effectiveness of shielding, lowest fabrication cost and environment-friendly shield.

Predicting and optimizing the physical and spectroscopic properties of phosphate laser glasses using a phase diagram approach

AbstractDespite the significant technological applications of laser glasses, the quantitative prediction and optimization of their properties, particularly the spectroscopic properties, remain challenging. Here we address this problem by regarding the nearest‐neighboring congruently melting compounds as the “component and structural motifs” based on the phase diagram approach. The composition–structure–property (CSP) relationships of Nd3+‐doped ternary phosphate glasses are investigated. Spectroscopic properties are quantitatively predicted with an error of less than 10% compared to the experimental results. In particular, the fluorescence lifetime (τm) can be accurately calculated using the phase diagram approach, which is difficult to be predicted previously. Furthermore, the CSP databases with over 1000 compositions are established for the optimization of commercial laser glasses. This study enriches the CSP database of traditional laser glass and provides guiding significance for future research.

Characteristic studies on Ag2O-Al2O3-P2O5 glasses and glass ceramics

Glass structure comprising (0–20) mol% Al2O3–(20–40) mol % Ag2O-and 60 mol % P2O5 was examined using a 27Al, 31P MAS- NMR and FTIR spectroscopy. The structural changes within the complicated ternary phosphate glasses were correlated with that of a simple binary silver phosphate. Results show that aluminum acts primarily as intermediate ions, while silver acts as a potent modifier. The number of non-bridging oxygen atoms (NBO) on average in the structure of silver aluminophosphate (SAP) glasses decreases with increasing Al2O3 content. The aluminum ions in the SAP glass system occur in the coordinations of both Al (6) and Al (4). The Al (6) fraction rises with rising concentration of Al2O3. Al (6) is more than Al (4) in the glass containing more Al2O3 than that of 20 mol of Al2O3. The glass was transformed into a glass-ceramics by the effect of thermal heat treatment at 600 °C for 4 h.

The Relationship among Electronic Polarizability, Photoelasticity, and Refractivity in Ternary Phosphate Glasses

The optical properties and structural relationships of ternary meta‐ and pyro‐phosphate glasses are found to be correlated with electronic polarizability. In particular, the optical properties of photoelasticity and refractivity have similar tendencies with electronic polarization evolution, which can be estimated from the Lorentz–Lorenz equation and the compositional data of reported electronic polarizability with small corrections with structural viewpoint. Combinations of the oxide constituents of BaO, SnO, and ZnO result in systematic changes of optical properties, which can be attributed to the phosphate‐anion network revealed by 31P magic‐angle spinning nuclear magnetic resonance spectroscopy. The small photoelastic constants are obtained with the ubiquitous high polarizable cation of Ba2+ and the substitution of Sn2+ with Zn2+ in the ternary phosphate glasses.

Terbium concentration effect on magneto-optical properties of ternary phosphate glass

Ternary phosphate glass doped with different terbium concentration (up to 35 wt.%) is synthesized via standard melt-quenching technique. The effect of terbium content on physical, optical, and magneto-optical properties is investigated. Two glass transition regions on DSC curve at 35 wt.% Tb2O3 demonstrate phase-separation process. Transmittance spectra demonstrate maximum 0.2 cm−1 level in optical transmittance window of 400–1600 nm limited by standard absorption bands for terbium-containing materials. Metaphosphate groups in as-synthesized glass structure are predominant over polyphosphate complexes with no ultraphosphate units regardless to composition changes. After the additional heat treatment the partial depolymerization of glass structure occurs resulting in formation of big amount of Q0 and Q1 units. Glass refractive index varies from 1.5872 to 1.5814 with terbium content increase. The concentration dependence of Verdet constant is non-linear due to the presence of Tb4+ ions, which was confirmed by the XPS analysis results. The value of 15 rad/T/m at 1064 nm is reached for 35 wt.% Tb2O3-doped glass. The results indicate the viability of the considered glass series with high terbium oxide concentration to be attractive media for magnetooptical devices working in VIS and near IR ranges.

Influences of ZnO on the chemical durability and thermal stability of calcium iron phosphate glasses

This study aims to investigate influences form zinc oxide on glasses in xZnO-(100-x) (54P2O5-36Fe2O3-10CaO) (x = 3,6,9,12,15,18 mol%). Structure analyses were carried by FTIR, and chemical durability tests were introduced to study changes in dissolution rate and weight losses. Thermal stability properties were measured and discussed through DSC. Results from structure changes indicate that glass network turns less compact with more ZnO, the building units gradually evolving into Q0 groups from Q1 tetrahedra, even the whole glass system locates in orthophosphate glasses. Higher melting temperature results in more Fe2+ that would lead to octahedral and disordered octahedral in the prepared glasses also contributing to open glass network in glass structure. The resistance in both alkali and acid solution were deteriorated for the sake of the open network, accompanied with the less strong P-O-Zn bonds when compared with the P-O-P bonds. Reasons accounting for the weak resistance also refer to the transition from [ZnO6] to [ZnO4], larger volume of [ZnO4] than that of [PO4], small particle size in ternary phosphate glasses. Drops in weight loss for each test span with corrosion time might be owing to the formation of alter layer on the surface of glass samples during corrosion. The phenomenon in water also follow the similar trend as those in the other two solutions for the same reasons. The glass transition and crystalline temperatures of all glasses drop as the degree of polymerization in glass becomes small, with four glass stability parameters falling as the amount of ZnO rises.

Comprehensive study on physical, elastic and shielding properties of lead zinc phosphate glasses

A series of ternary phosphate glasses in the form of (PbO)x(ZnO)60-x(P2O5)40 where x=0–60mol%, have been successfully prepared by conventional melt-quenching technique. The physical and elastic properties of the glasses have been investigated using pulse echo technique. The longitudinal and shear velocity of the glasses were measured using the MBS8000 ultrasonic data acquisition system at 10MHz frequency in room temperature. The density, ultrasonic velocity and elastic moduli are found to be composition dependent and the correlation between the elastic moduli with the atomic packing density is discussed in detailed. The shielding parameters, mass attenuation coefficients, half value layers and exposure buildup factor (EBF) values have been computed using WinXCom program with the use of GP fitting method, and variation of shielding parameters are discussed for the effect of PbO addition into the glasses and photon energy. An increase in the density of the glasses results in a change in crosslink density. The sound velocity and elastic properties increased with PbO content and increase in Poisson's ratio trend suggests that the rigidity of the glasses has decreased. Besides, the replacement of ZnO by PbO causes an increase in mass attenuation coefficient, while the half value layer and the exposure buildup factor were decreased and these glasses has been potentially used as shielding material.

Modifier Interaction and Mixed-Alkali Effect in Bond Constraint Theory Applied to Ternary Alkali Metaphosphate Glasses

Introducing an interaction parameter γ, we implement modifier interaction and the mixed-alkali effect into bond constraint theory, and apply this extension for simplistic property prediction on ternary phosphate glasses. The severity of the mixed alkali effect results from the interplay of two simultaneous contributions: Bond constraints on the modifier species soften or stiffen with decreasing or increasing γ, respectively. When the modifier size is not too dissimilar the decrease in γ reflects that the alkali ions can easily migrate between different sites, forcing the network to continuously re-accommodate for any subsequent distortions. With increasing size difference, migration becomes increasingly difficult without considerable network deformation. This holds even for smaller ions, where the sluggish dynamics of the larger constituent result in blocking of the fast ion movement, leading to the subsequent increase in γ. Beyond a certain size difference in the modifier pair, a value of γ exceeding unity may indicate the presence of steric hindrance due to the large surrounding modifiers impeding the phosphate network to re-accommodate deformation.

Effect of PbO on the elastic behavior of ZnO–P2O5 glass systems

A series of ternary phosphate glasses in the form of 40(P2O5)–(60−x)ZnO–xPbO and 50(P2O5)–(50−x)ZnO–xPbO where x=0–60mol%, have been successfully prepared by conventional melt quenching technique. Both longitudinal and shear ultrasonic velocities were measured in different compositions of PbO using the MBS8000 ultrasonic data acquisition system at 10MHz frequency and at room temperature. The ultrasonic velocity data, the density and the calculated elastic moduli are found to be composition dependent and discussed in terms of PbO modifiers. The correlation of elastic moduli with the atomic packing density of these glasses was discussed. To predict the compositional dependence of elastic moduli of this glass system, the interpretation of the variation in the experimental elastic behavior observed has been studied based on various of the bond compression and the Makishima–Mackenzie models.

Decay kinetics and energy transfer in ternary phosphate glass doped Eu and Eu/Dy

Different series of glass samples with different glass compositions and different concentrations of rare earth ions (Eu and Eu/ Dy co-doped) were prepared. Excitation and photoluminescence spectra were measured, for which the observed peaks are attributed to the f-f transitions of the rare earth ions. Decay kinetics of the characteristic emission peaks were registered and investigated using Inokuti-Hirayama model (IH model),when the emission decay deviated from the exponential pattern to study energy transfer in the prepared samples. The IH model is used to determine the energy transfer parameter which is correlated to the glass composition factor.

Slow release of phosphate glass and its applications in the lead-contaminated soil remediation

ABSTRACTThis study examined the dissolution release performance of slow-release phosphate glass (SRPG), and the role this element plays in water and soil contaminated with heavy metals. It is known that the rate of dissolution ternary phosphate glass as XMgO–(50-X)Na2O–50P2O5 (mol %) may be controlled by adjusting its content of MgO. The results showed that SRPG was uniformly dissolved in deionized water. Acidic or basic conditions induced the dissolution of SRPG; in contrast, lysate of SRPG in water decreased its rate of dissolution. Phosphate glass treatment of heavy metal lead (Pb)-contaminated soil effectively reduced the Pb content in H2O and MgCl2 extracts by 81.6% and 75.7%, respectively. Comparative tests showed that leaf and root portion of Pb uptake in cabbage grown in soil treated with SRPG was reduced by 65.1% and 51.6% compared to untreated soil. Analysis of SRPG with Pb immobilization in water and soil environment by X-ray diffraction demonstrated that low-solubility phosphate (PbHPO4) and hydroxyphosphate [Pb5(PO4)3OH] complex was formed. Data indicate that SRPG may be effective in removal of Pb from contaminated soils and diminish risk of toxicity from ingestion of this heavy metal by consumers.

Synthesis and study by FTIR, 31P NMR and electrochemical impedance spectroscopy of vanadium zinc phosphate glasses prepared by sol–gel route

Ternary phosphate glasses of the system (ZnO)(0.45−x)–(P2O5)(0.55−y)–(V2O5)z, (y=0; x=z=0.01, 0.1; 0.2) and (x=0, y=z=0.1; 0.2) are prepared via the sol–gel process using zinc acetate, ammonium metavanadate and phosphoric acid as precursors. Spectroscopic investigations reveal a phosphate glass system depolymerization by systematic conversion of PO3− metaphosphate chains into (P2O7)4− pyrophosphate, with the formation of P–O–V and V–O–V bonds, which replace P–O–P ones. Heat treatment of the dried xerogels containing 10% of V2O5 at temperatures 400–600°C shows a similar trend in their infrared spectrum then that of glass obtained by melt quenching at 1000°C. Inhibitive effect of the glass composition (ZnO)0.45–(P2O5)0.45–(V2O5)0.1 obtained at 600°C and 1000°C in simulated water was studied by electrochemical impedance spectroscopy (EIS). Inhibitory efficiency for both samples is the same ~95%.

Thermal and optical properties of BaO–CaF2–P2O5 glasses

Thermal and optical properties of ternary phosphate glasses prepared by conventional melt-quenching technique, belonging to the series (50−X)BaO–XCaF2–50P2O5 (X=0 to 10mol%) were investigated with increase in CaF2 content. Thermal stability and glass forming ability studied using differential thermal analysis (DTA) were found to increase with the increase in CaF2 content. Powder X-ray diffraction (XRD) analysis of heat treated samples also revealed that CaF2 addition improves the thermal stability against crystallization. Increase in both glass transition temperature and onset crystallization temperature with the increase in CaF2 content can be attributed to the partial substitution of Ba2+ ion with Ca2+ ion, which is having larger field strength. The observed decrease in the melting temperature of glass batch with the increase in CaF2 content indicates that CaF2 acts as a flux and reduces the viscosity of the glass melt. The decrease in refractive index of the glasses with the increase in CaF2 content can be attributed to replacement of lower field strength Ba2+ by Ca2+ or the partial substitution of more polarizable oxygen ion by fluorine. Optical band gap energy slightly increased and Urbach energy marginally reduced with the increase in CaF2 content. Increase in optical band gap energy was further confirmed by calculating theoretical optical basicity of glasses. Average anion polarizability (αO/F) of (50−X)BaO–XCaF2–50P2O5 glasses calculated from refractivity data using Lorentz–Lorentz relation was correlated with its theoretical optical basicity (λth) using the previously established correlation for oxyfluoro phosphate glasses.

Structural, optical and mechanical properties of ternary CaO-CaF2-P2O5 glasses

The ternary phosphate glass series (50−x)CaO-xCaF2-50P2O5 (x = 0–20 mol%) were synthesized using melt quench technique. Structural, optical and mechanical properties were investigated with increase in CaF2 content. Using X-ray diffraction (XRD), synthesized glasses were confirmed to be amorphous in nature. Replacement of oxygen ions by fluorine ions increased the values of density. Decrease in refractive index due to the low polarizability of fluorine ions in the glass matrix was observed. In Fourier transform infrared (FTIR) spectra, the slight variation in νas (PO2) band position and intensity could be attributed to replacement of fluorine ions for oxygen ions in phosphate glass structure. These data were well supported by Raman spectra. Optical band gap energy increased from 3.44 eV to 3.64 eV with increase in CaF2 content, and Urbach energy decreased suggesting that the fluorine ions reduced the tail energy states in the band gap compared to the oxygen ions. Mechanical parameters such as Vickers hardness, fracture toughness and brittleness were evaluated from the Vickers micro indentation measurements. Increase in Vickers hardness, decrease in fracture toughness and increase in brittleness were observed with increase in CaF2 content.

Relationship between absorption edge and local structure around bismuth ions in bismuth-containing ternary phosphate and borate glasses

Relationship between absorption edge and local structure around bismuth ions in bismuth-containing ternary phosphate and borate glasses

Modelling the structural evolution of ternary phosphate glasses from melts to solid amorphous materials.

The local and medium-range structural properties of phosphate-based melts and glasses have been characterized by means of first principles (density functional theory) and classical (shell-model) molecular dynamics simulations. The structure of glasses with biomedically active molecular compositions, (P2O5)0.45(CaO)x(Na2O)0.55-x (x = 0.30, 0.35 and 0.40), have been generated using first principles molecular dynamics simulations for the full melt-and-quench procedure and the changes in the structural properties as the 3000 K melt is cooled down to room temperature have been compared extensively with those of the final glasses. The melts are characterized by a significant fraction of threefold (P3c) and fivefold (P5c) phosphorus atoms, but structural defects rapidly decrease during the cooling phase and for temperatures lower than 1800 K the system is free of under- and over-coordinated species. The analysis of the structures of the glasses at 300 K shows a prevalence of the metaphosphate Q2 and pyrophosphate Q1 species, whereas the number of Q3 units, which constitute the three-dimensional phosphate network, significantly decreases with the increase of calcium content in the glass. The radial and angular distribution functions indicate that higher calcium concentration in the glass leads to an increase of the rigidity of the phosphate tetrahedral network, which has been explained in terms of the calcium's higher field strength compared to that of sodium. The structural characterization of the melts and glasses obtained from first principles simulations was used to assess and validate a recently developed interatomic shell-model forcefield for phosphate-based materials. For all three compositions, our potential model is in good agreement with the first principles data. In the glass network, the forcefield provides a very good description of the split between the shorter distances of phosphorus to non-bonded oxygen and the longer distances of the phosphorus to bonded oxygen; the phosphorus-phosphorus medium-range distribution; and the coordination environment around the Na and Ca glass modifiers. Moreover, the distribution of the Qn species in the melts and glasses is in excellent agreement with the values extracted from the first principles simulations. In contrast, simulations using standard rigid ion potentials do not provide a satisfactory description of the local short-range structure of phosphate-based glasses and are therefore less suitable to model this class of multicomponent amorphous system.

Zinc borophosphate glasses for infrared-based optical applications

A series of ternary phosphate glass systems required for infrared (IR) photonic device fabrication is synthesized by the melt-quenching technique. The effect of replacing (divalent) ZnO with (monovalent) Na 2 O on optical properties of the glass systems is investigated. The dependence of the refractive index on composition is measured over a wavelength range of 1 to 2.5 μm; the second-order nonlinear refractive index is inferred. The different factors that play a role on controlling the glass refractive index, such as electronic polarizability, bridging and non-bridging oxygen, optical basicity, and ionic interaction parameter of oxides are discussed. IR vibrational spectroscopy is used as a structural probe of the nearest neighbor environment in the glass network. The present glasses are proper to be applied in C -band telecommunication systems around 1550 nm.

Optical properties of ternary zinc magnesium phosphate glasses

Ternary phosphate glasses of the system (ZnO) 30(MgO) x (P 2O 5) 70− x with x ranging from 5 to 20 mol% were prepared by melt quenching technique. The optical absorption spectra of these glasses were measured at room temperature in the wavelength range between 190 and 1100 nm while the refractive index at wavelength 632.8 nm. The optical absorption indicates that the electronic transition is indirect and associated with phonon-assisted transition. From the absorption spectra, the optical energy band gap ( E opt) and Urbach energy ( E U) values for all the glass samples were calculated from their ultraviolet edges. The values of E opt is found to increase from 3.36 to 3.44 eV and values of E U decrease from 0.47 to 0.29 eV with the increase of MgO content. Variation in these optical parameters, density and molar volume is discussed and correlated with the structural changes within the glassy matrix.

Structural and Textural Modifications of Ternary Phosphate Glasses by Thermal Treatment

Phosphate‐based glasses of composition xNa2O−(45+(10−x))CaO−45P2O5 with different Na2O, CaO (x = 1, 5, 10, 15, and 20 mol%), and invariable P2O5 (45 mol%) contents were prepared using the rapid melt quench technique. The obtained thermal data from differential thermal analysis revealed a decline in glass transition (Tg) and crystallization (Tc) temperatures of glasses against the compositional changes. The inclusion of Na2O at the cost of CaO in the glass network led to a reduction in its thermal stability. The thermal treatment carried out on glasses helped to derive their glass‐ceramic counterparts. The amorphous and crystalline features of samples were characterized using X‐ray diffraction patterns. The crystalline species that emerged out of the calcium phosphate phases confirmed the dominance of Q1 and Q2 structural distributions in the investigated glass‐ceramics. The obtained scanning electron micrographs and atomic force microscopic images confirmed the surface crystallization and textural modification of the samples after thermal treatment. The N2‐adsorption–desorption studies explored the reduction of porous structures due to thermal treatment on the melt‐driven glass surface. The measured elastic moduli and Vicker's hardness values of the glasses showed an increase after thermal treatment, which were reduced against the inclusion of alkali content in both glass and glass‐ceramics.