Parent Glass Research Articles

Exploring the optical properties of the 1.53 μm emission in Er3+-doped glass, anti-glass and ceramic in TeO2 - Ta2O5 – Bi2O3 system

A series of 80TeO2 - 10Ta2O5 – 10Bi2O3 glasses, anti-glasses and ceramics doped with different concentrations of Er₂O₃, ranging from 0.25 % to 2 % mol, were synthesized to explore their structural transformation and optical properties. The maximum solubility of Er₂O₃ was identified at 1.25 % mol, beyond which the glass transitioned from an amorphous to a crystalline structure. The anti-glasses and ceramics obtained from the heat treatment of the parent glasses were also studied to gain insights into their optical properties. This study reveals a direct relationship between Er3+ ions concentration and full width at half maximum (FWHM) of photoluminescence spectra. The increase in Er3+ ions concentration correlates with a rise in FWHM, indicative of spectral broadening. Anti-glass exhibits a higher emission intensity, followed by ceramic and then glass, reflecting their distinct structural properties. Anti-glass doped with 1 % mol Er2O3 shows an FWHM over 130 nm under 578 mW pumping. The lifetime of the excited state 4I13/2 increases with the Er2O3 content in the anti-glass and the ceramic, with a notable decrease at 1 % mol Er2O3 ions for both materials, while in glass, the decrease is observed at 0.5 %. Emission cross-sections decrease with increasing Er3+ ions concentration and power, influenced by factors like thermal effects and saturation. The Judd-Ofelt theory highlights structural differences, with glasses having a more disordered structure and with an increase in the Ω₆ parameter across all materials, implying enhanced electric dipole line strength and spontaneous emission probability with higher Er₂O₃ content. Overall, this comprehensive study provides valuable insights into the optical behavior of Er3+ ions in these materials, essential for applications in laser design and optical amplifiers.

Altering the optical, physical, and TL Dosimetric properties of MgSO4:Dy2O3:B2O3 transparent glass ceramic system: Evaluating the impact of roughness control and ZnO inclusion

This research examines the influence of surface roughness and the incorporation of ZnO (0.05–0.20 mol%) on the magnesium sulfate: dysprosium oxide: boron oxide (0.1 < x < 0.5) glass ceramic system for dosimeter applications. The parent glasses were prepared using the melt-quenching technique, with all samples melted at 1350 °C, except for B, which was melted at 700 °C. The crystallization, roughness, and optical properties were further determined using X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), and UV–Visible Spectrophotometry, respectively. The glass ceramics were exposed to 2.97 mGy of X-ray radiation ten cycles to assess specific dosimetric capabilities. Among the doped samples, MgSO4:Dy2O3-(0.2B2O3:0.05ZnO) exhibited the most promising performance as a dosimeter. Notably, the Thermoluminescence Dosimetry (TLD) readings of the pre- and post-polished 0.2MDB were 1041.96 nC and 1278.84 nC, respectively, with roughness values of 1.83 nm and 54.7 nm. Similarly, the TLD readings of the pre- and post-polished 0.05MDBZ were 1888.33 nC and 3262.63 nC, respectively, with roughness values of 17.3 nm and 19.8 nm. This work highlights that surface roughness significantly enhances trapping efficiency, underscoring the importance of dosimeter polishing as a beneficial step in enhancing their performance.

Structural features and thermal expansion of zinc aluminosilicate quartz solid solutions

Zinc aluminosilicate (ZAS) glasses were synthesized along the peraluminous join (SiO2 contents between 95 and 50 mol%) by melt-quenching or sol-gel spray-drying and subjected to controlled heat treatments to obtain ZAS quartz solid solutions (Zn-Qz-ss). The precipitation of Zn-Qz-ss is non-stoichiometric with respect to their parent glass and the crystals undergo a compositional evolution during annealing, even in absence of secondary crystalline phases. Near-hexagonal high-quartz-like crystals with negative thermal expansion (down to −3 × 10−6 K−1) can be obtained in the range 50–80 mol% SiO2, while SiO2-richer crystals exhibit positive thermal expansion at room temperature (up to 29 × 10−6 K−1). Zn2+ ions occupy two distinct positions within the structural channels of quartz, with a strong preference for 4-fold coordination. In analogy to lithium aluminosilicate quartz solid solutions (Li-Qz-ss), the low-to-high phase transition exhibits a linear correlation to the composition of the crystals.

Near pure white light emission of CeO2-Dy2O3 co-doped K2O–MgO–B2O3–P2O5 glasses and glass-ceramics

In this paper, the Ce3+/Dy3+ co-doped K2O–MgO–B2O3–P2O5 glasses (KMBP system) were produced, and the glass-ceramics (GC) were obtained by thermal treatment. The structure and fluorescent characteristics of the glasses and GC were analyzed by structural characterization, Judd-Ofelt (J-O) theory and photoluminescence spectra. Thermal analysis revealed that the KMBP system exhibited a stronger crystallization ability. The J-O parameters of the as-prepared glasses were found to all obey the order as Ω2 > Ω4 > Ω6. Spectral analysis showed that the glass doped with 0.5Ce3+/0.2Dy3+ rendered the nearly pure white light emission and featured a near-zero color purity of 1.23% as well as a correlated color temperature of 5071 K near that of daylight, standard white light and commercial WLEDs. The energy between Ce3+ and Dy3+ ions was transferred dominantly through dipole-dipole interactions, as determined by the Inokuti-Hirayama model. Additionally, the GC sample obtained from the parent glasses nucleated at 520 °C for 1 h and then crystallized at 590 °C for 0.5 h showed the optimal fluorescent properties. The higher activation energy Ea (0.302 eV) value of the GC sample implied that the Ce3+/Dy3+ co-doped KMBP glass-ceramics possessed stronger fluorescent thermostability. This indicates the potential of the as-prepared glass-ceramics for WLEDs.

Effects of P2O5 content on the structure, stress distribution and vickers hardness of Na2O-MgO-Al2O3-SiO2 glasses with chemical strengthening treatments

In this work, effects of P2O5 content on the structure, stress distribution and vickers hardness of alkali aluminosilicate glasses with different chemical strengthening treatments were investigated. The results showed that the addition of P2O5 increased the degree of polymerization for glass network. The coefficient of thermal expansion, glass transition temperature and density of the parent glasses were all decreased. Meanwhile, the molar volume of the samples increased. The chemical strengthening experiments revealed that increasing P2O5 content promoted the diffusion of K+ ions, which resulted in an increase in the depth of stress layer. However, surface compressive stress of the glasses decreased with P2O5 content increasing, mainly attributed to stress relaxation of the glass structure. After chemical strengthening treatments at 370 °C and 390 °C respectively, the vickers hardness of the glasses decreased with the increase of P2O5, while an opposite trend was observed at 410 °C.

Optimized growth of LiZnBO3 monoclinic phase in lithium zinc borate glass ceramics for electrode material

Glass-ceramics (GCs) of glass composition 20ZnO.30Li2O.50B2O3 were prepared via controlled heat treatment at hold times of 2h, 4h, 6h and 8h at crystallization peak temperature (846K). The effect of the hold time of heat treatment on the physical, structural, optical, and electrochemical properties was studied. XRD study revealed the formation of a pure LiZnBO3 crystalline phase. FTIR study revealed the transformation of BO4 units to BO3 units with an increase in the time of heat treatment. Optical band gap energy has been estimated from Diffuse Reflectance spectroscopy and, its values range from 3.26eV–3.36eV. Electrochemical properties were studied using Cyclic Voltammetry and compared with parent glass composition. The GC 20ZnO.30Li2O.50B2O3 heat treated for 8h exhibits the highest value of specific capacitance (∼48 mAh/gV) and energy density (∼18 J/g) indicating that it can be used as an electrode material in Li-ion batteries.

Preparation of some selective glass–ceramics from nano-silica within the Li2O–SiO2 system with ZrO2 for future dental applications

Many recent studies have indicated that some modified silicate glass–ceramics are considered and recommended to be part of the process of dental applications. Examples from the recommended glass–ceramics include modified lithium silicate with various dopants (ZrO2, CeO2), mica-based glass–ceramics, and leucite-based glass–ceramics. The present study employs a new direction of research in the preparation of modified lithium silicate glasses containing varying dopant percents of ZrO2 to produce the parent glasses using nano-silica as an essential chemical component in comparison with silica. The ZrO2-doped glass–ceramic reveals the crystalline phase of lithium aluminosilicate (Li5AlSi2O8) due to the effect of ZrO2. The modified lithium silicate glasses doped with ZrO2 prepared from nano silica indicate their high mechanical properties and can be primarily recommended for dental applications.

Linking molecular origin of melt fragility index with topological phases of network glasses

Network glasses are composed of three topological phases: flexible, intermediate, and stressed-rigid. Intermediate Phase (IP) glasses form compact, rigid, and stress-free networks with noOpen Degrees of Freedom (ODF). IP melts are observed to be super-strong with the lowest fragility index, m = 15 due to the absence of ODF in the parent glass. This feature is general and observed in multiple selenide, sulfide, and modified oxide glasses can be traced to Isostatically Rigid Local Structures (ISRLSs) formed in the IP. On the other hand, the flexible and stressed-rigid phase glasses form non-compacted and stressed networks with increasing residual pressure as the count of ODF increases. Their melts are found to be fragile and display fragility indices m > 20 as the count of the ODF in the glass increases and the count of ISRLSs dissipates.

Enhancement of damage resistance of transparent Li2O-Al2O3-B2O3 glass by crystallization

Aluminoborate glasses exhibit remarkable crack-resistance properties, rendering them a promising material for cover glasses in portable electronic devices. However, their usage has been hindered by their relatively low hardness. To address this challenge, a parent glass with 11 Li2O-30 Al2O3-55 B2O3-2 TiO2-2 P2O5 (wt%) was prepared using a melt-cast method. Heat treatment at 575 °C yielded a glass-ceramic (G-575) with a Vickers hardness of 6.51 GPa, 40.91 % higher than the parent glass due to structural densification and Li(Al7B4O17) crystalline phase precipitation, improving indentation fracture toughness from 0.97 to 1.79 MPa·m1/2. Additionally, the glass-ceramics demonstrated a visible transmittance of approximately 85 % and a cracking resistance (CR) value of 14.8 N. Scratch tests conducted at a constant force revealed that the comprehensive damage resistance of glass-ceramics surpassed that of the parent glasses, making it a promising cover glass material.

Mesoporous bioactive scaffolds based on the 14.6Li2O⋅8.6ZrO2⋅67.3SiO2⋅9.5Al2O3 glass-ceramic as drug delivery for bone regeneration

Bioactive scaffolds based on the 14.6Li2O⋅8.6ZrO2⋅67.3SiO2⋅9.5Al2O3 glass-ceramic for use in drug delivery is presented. Powders of the parent glass (212 mm > particle size >38 mm) were heat-treated at 725 °C for 3 h for surface crystallization. They were subjected to a chemical attack with 6 vol% of hydrofluoric acid for 40 s for partial dissolution of the residual glass, and washed with deionised water and calcium carbonate. Structural and microstructural analyses were performed to identify the formed crystalline phases and porosity. Mesopores with 2.05 nm-radius were detected. The immersion method was used to insert alendronate sodium into the scaffolds. The drug delivering capability was evaluated by infrared spectroscopy and thermogravimetric analysis (TG). The FTIR spectra showed the typical functional groups existing in the alendronate sodium, confirming their impregnation into the scaffold's pores. Moreover, the TG thermograms showed loss weights of ∼2% indicating the effective inoculation of the drug into the scaffold. The bioactivity of the material was evaluated through calcium phosphate layer formation after incubation in a simulated body fluid for up to 28 days (37 ± 1 °C) and then analysed by infrared spectroscopy (FTIR). Calcium phosphates were identified after 24 h of immersion indicating the bioactivity of the glass-ceramic. The cytotoxicity and hemocompatibility tests showed that the LZSA glass-ceramic scaffold is not considered toxic to the human body at concentrations below 40 μg/mL and does not show hemolytic effects at all tested concentrations. Thus, the obtained microstructure renders the material promising for use as a drug delivery agent for bone regeneration.

Preparation of Li2O–Al2O3–SiO2–B2O3（LASB）glass-ceramic with low thermal expansion coefficient from spent hydrogenation catalysts and crystallization kinetics

The recovery of spent hydrogenation catalysts occupies advantages in both alleviating environmental burden and resource shortage. Whereas, the development of conventional hydrometallurgical recovery of molybdenum (Mo) and nickel (Ni) from spent MoNi/Al2O3 catalysts has been limited by the numerous processes and the accompanying generation of waste liquids and residues. Herein, A new recycling route for the preparation of spent hydrogenation catalysts with low thermal expansion coefficients (CTE) was proposed, which has the advantages of short process, green environment and high value utilization. The Li2O–Al2O3–SiO2–B2O3 (LASB) parent glass containing Mo and Ni were obtained by melting with different contents of the spent catalysts. The thermal expansion coefficient of the glass was minimized to 6.08 × 10−6/°C at an addition of 25 wt% of the spent catalysts. Moreover, according to the crystallization peak in DTA curve, glass-ceramics were prepared by one-step crystallization heat treatment at different crystallization temperatures. The main crystalline phase of the glass-ceramic precipitated by heating at 685 °C is β-quartz (Li2Al2Si3O10), which gives the glass-ceramics the lowest coefficient of thermal expansion (0.96 × 10−6/°C) of glass-ceramic as well as the maximum density (2.45 g/cm3) and Vickers hardness (705.8 Hv). Furthermore, the activation energy (354.65 ± 17.42) kJ/mol) and Avrami index (5.39) associated with crystallization were extracted from the fitting of different theoretical model, indicating the three-dimensional crystallization of the LASB glass-ceramics. This technology provides a waste-to-material strategy for hazardous waste and a clean production route for the preparation of the functional glass-ceramics.

Bioactive glass–ceramics containing fluorapatite, xonotlite, cuspidine and wollastonite form apatite faster than their corresponding glasses

Crystallisation of bioactive glasses has been claimed to negatively affect the ion release from bioactive glasses. Here, we compare ion release and mineralisation in Tris–HCl buffer solution for a series of glass–ceramics and their parent glasses in the system SiO2–CaO–P2O5–CaF2. Time-resolved X-ray diffraction analysis of glass–ceramic degradation, including quantification of crystal fractions by full pattern refinement, show that the glass–ceramics precipitated apatite faster than the corresponding glasses, in agreement with faster ion release from the glass–ceramics. Imaging by transmission electron microscopy and X-ray nano-computed tomography suggest that this accelerated degradation may be caused by the presence of nano-sized channels along the internal crystal/glassy matrix interfaces. In addition, the presence of crystalline fluorapatite in the glass–ceramics facilitated apatite nucleation and crystallisation during immersion. These results suggest that the popular view of bioactive glass crystallisation being a disadvantage for degradation, apatite formation and, subsequently, bioactivity may depend on the actual system study and, thus, has to be reconsidered.

Structural investigation and effect of gamma-ray irradiation on barium borate glasses containing vanadium oxide

This work investigates the structural changes induced in barium borate glasses by gamma irradiation doses and vanadium doping using FTIR spectroscopic technique. Binary Barium borate parent glass and samples of the same composition containing different concentrations of vanadium oxide with formula xV2O5-(65-x)B2O3-35BaO (x = 0, 2, 4, 6, 8, and 10) were synthesized by melt quenching technique. FTIR spectroscopy approves the formation of both BO3 trigonal and BO4 tetrahedral structural units within the network backbone. V2O5 additions lead to borate network depolymerization by breaking B-O-B bonds and increasing V2O5 content causes systematic reductions in boroxol rings and B-O-B linkages, indicating disruption of the borate network. Gamma irradiation also damages the borate structure by cleaving B-O-B bonds in boroxol rings and BO3 units. This progressively converts BO3 to BO4 groups. Infrared spectroscopy reveals decreases in BO3 vibrations at higher doses as the network degrades. The radiation-induced network damage leads to changes in glass properties including thermal stability and hardness. A clearer understanding of borate structural modifications helps target these glasses for optical devices with controlled properties.

Preparation and Characterization of Nano Glass–ceramics from CeO2-doped Li2O-SiO2 System for Dental Applications

Glasses based on the basic composition of lithium disilicate (Li2O.2SiO2) together with derived samples containing increasing CeO2 replacing Li2O (0.1, 0.2, 0.5, 1 Mol %) were prepared by melting – annealing method, samples from the prepared parent glasses were thermally heat treated through two-step regime (450° C /10 h – followed by 650° C / 6 h) to convert them to their glass – ceramics derivatives. The main purpose of this study is to find out the main properties of the prepared glass – ceramics to be applied as dental candidates. The optical, FTIR, and thermal expansion properties of the parent glasses were examined to identify the main structural groups which are defined as tetrahedral stronger SiO2 building groups. The detailed separated crystalline phases within the prepared glass–ceramics were identified together with their textural features. The Vickers microhardness data for both the parent glasses and their glass -ceramics derivatives were evaluated. SEM and EDAX measurements indicate the ability of the prepared samples to form hydroxyapatite upon immersion in SBF solution.

Effect of NiO, ZrO2 and TiO2 on the formation of glass-ceramic cordierite in the MgO–Al2O3–SiO2–MoO3 system

In glass-ceramic design, the two most crucial factors are composition and microstructure both factors control the ability to form a glass and determines its degree of workability. The composition also determines whether internal or surface nucleation can be achieved. If internal nucleation is desired, as is the case in hot forming glassware, right nucleating agents are melted into the glass as part of the bulk composition. For this reason, this research work focuses on obtaining glass-ceramic cordierite starting from a parent glass of the MgO–Al2O3–SiO2–MoO3 system, using NiO, ZrO2 and TiO2 in a range of 1%Wt to 3%Wt, with the objective of identifying which of the oxides most favors the formation of cordierite. Twelve samples were prepared, which were characterized by thermal gravimetric analysis (TGA), differential thermal scanning analysis (DSC), X-ray diffraction (XRD), Elemental X-ray mapping (SEM), and Infrared spectra using the ATR technique (FT-IR). It was found that NiO is the oxide that most promotes the formation of the cordierite phases, in addition to the use of molybdenum as part of the parent glass, which lowers the crystallization temperature of the crystalline phases obtained. This is determined with the results of phase quantification using the Rietveld method, by XRD, where the samples with NiO add up to a content greater than 90 % of cordierite α and β. And it is supported by the SEM results, where the characteristic hexagonal morphologies of cordierite are identified, the IR characterization results where the bands of the bonds of the phases identified by XRD are identified.

One-step preparation of bi-layer foamed glass-ceramics using asynchronous oxidization of SiC and B4C

Bi-layer foamed glass-ceramic has the advantages of both dense and foamed structure which lead to low bulk density and high mechanical strength. We propose a new one-step method to produce bi-layer foamed glass-ceramic using the asynchronous oxidization of B4C and SiC. The parent glass is prepared by melting-quenching method, followed by foaming through powder sintering route with addition of B4C and SiC. The bi-layer structure and formation of bi-layers are investigated by scanning electron microscope (SEM), X-ray computed tomography, 11B NMR, and high temperature melting observation system (HTMOS). The results show that during the sintering process, the oxidization of B4C in top layer at low temperature forms boron oxide and helps the formation of glass melt in the top layer. The oxidization of SiC at high temperature leads to foaming in the top layer. The prepared bi-layer foamed glass-ceramic has low bulk density of 1.06 g·cm−3 and high flexural strength of 26.15 MPa.

Energy transfer modulation of photoluminescence in glasses co-doped with Nd3+ and CsPbBr3 quantum dots

Nd3+ co-doped CsPbBr3 perovskite quantum dots (PQDs) glasses were prepared by conventional melt-quenching followed by a thermal treatment process. With the introduction of Nd2O3 to the parent glass, the optical properties of the CsPbBr3 PQDs are significantly improved. The energy transfer from CsPbBr3 PQDs to Nd3+ ions was investigated and confirmed by excitation and emission spectra. The results show that visible excitation band width for the near-infrared (NIR) emission of Nd3+ ions is significantly increased in the presence of PQDs. The strategy for modulation of the optical properties by the energy transfer between rare earth ions and PQDs in the glass matrix could be further utilized for spectral engineering of photonic glasses for optoelectronic applications.

Influence of partial replacing of CaO by SrO on structure and bioactivity of calcium-phospho-silicate glasses

New alkali-free bioglasses of the ternary 60SiO2·5P2O5·35CaO parent glass wherein Ca is partially substituted by Sr (up to 10 mol%) were prepared by sol-gel method. The replacement of Ca with Sr induced the tendency to crystallisation of an apatite type phase. The bioactivity tested in vitro depends on Ca/Sr replacement degree, despite the fact that the theoretical network connectivity does not change with Ca/Sr substitution. After seven days of incubation in simulated body fluid, only on the samples with x ≥ 5 mol% SrO was developed a layer assumed of combined Ca/Sr composition of carbonated hydroxyapatite. Bactericidal activity was observed exclusively in case of strontium containing samples, for both Gram positive and negative bacteria. Structural effects of partial replacing of CaO by SrO were investigated by X-ray diffraction and FTIR analysis both before and after samples incubation in simulated body fluid.

Simultaneous oxidation of Mn2+ to Mn4+ by devitrification of transparent glassy Na2Ge4O9: Mn

To generate red emissions, manganese (IV) ions have recently gained recognition as potent non-rare-earth activators. However, the oxide and fluoride hosts that offer suitable environments for Mn4+ require careful preparation, involving precise control of reaction parameters like redox equilibrium and temperature. In the current work, we show simultaneous oxidation of Mn2+ to Mn4+ by devitrification of glassy Na2Ge4O9: Mn under moderate atmospheric conditions and under the argon atmosphere. The G-sample was devitrified via thermal treatment after the parent glass, which shares the same chemical formula as dilithium tetragermanate (Na2Ge4O9), was created through the use of traditional melt-quenching (MQ). Optical spectroscopy and electron paramagnetic resonance (EPR) spectroscopic are utilized to confirm the Mn2+ oxidation to Mn4+ from glass stat to glass ceramic after thermal treatment. Due to the transition from Mn2+ to Mn4+, a sharp 668 nm emission peak is recorded whereas the red emission peaking at 611 nm monitored in glass is steadily reduced. The temperature-dependent PL spectra of the Na2Ge4O9:0.1Mn+4, red-emitting GC in the temperature range ∼295–490 K were recorded. The PL emission intensity decreases gradually with increasing the temperature. The technique showcased for producing Na2Ge4O9:Mn4+ phosphors could be expanded to synthesize other phosphors incorporating activators possessing a high oxidation state.

Preparation and characterization of MgO-Al2O3-SiO2 glass-ceramics with different MgO/Al2O3 ratio and La2O3 addition

MgO-Al2O3-SiO2 (MAS) glass-ceramics were prepared by traditional melting and sintering method, and the effects of MgO/Al2O3 ratios and La2O3 contents on the microstructure and physicochemical properties of MAS glass-ceramics were studied. Herein, differential scanning calorimetry (DSC), X-ray diffraction (XRD), fourier-transform infrared spectrophotometer (FTIR), Field-emission scanning electron microscopy (FESEM), density, corrosion resistance, dielectric properties and thermal expansion coefficient (CTE) were carried out to evaluate the properties of both parent glass and glass-ceramics samples. The results show that adjusting the MgO/Al2O3 ratio from 0.69 to 0.47 can increase the characteristic temperatures of transition temperature (Tg) and crystallization peak temperature (Tp) in MAS parent glass. The reduction of MgO/Al2O3 ratio could promotes the precipitation of α-cordierite phase (Mg2Al4Si5O18), and the grain size of α-cordierite phase were increased from 200 to 500 nm. When the MgO/Al2O3 ratio was 0.63, the MA-2 sample has the highest flexural strength of 127.46 MPa. Furthermore, we also investigated the influence of La2O3 addition on the structure and properties of MAS glass-ceramics by employed MA-2 sample as a reference. The results show both the Tg (742–748 °C) and Tp (936–943 °C) of parent glass exhibit a slightly increasing with the La2O3 content was increased from 0.0 to 2.0 wt%. The La2O3 addition show a negligible influence on the crystal phase and morphology of MAS glass-ceramics. With increasing of the La2O3 content, the MAS glass-ceramics samples have a larger density (2.58–2.76 g/cm3) and a better chemical stability, and the CTE (6.12–8.17 × 10−6/°C), εr (5.04–6.17), and the flexural strength (127.46–150.15 MPa) also show an increased change trends. The prepared MAS glass-ceramics can be packaged with high expansion coefficient chips (such as GaAs) and is expected to become a potential candidate of dielectric materials for electronic devices, especially for high frequency applications in integrated circuits.