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1.
Due to their excellent optical properties, glasses are used for various applications ranging from smartphone screens to telescopes. Developing compositions with tailored Abbe number (Vd) and refractive index at 587.6 nm (nd), two crucial optical properties, is a major challenge. To this extent, machine learning (ML) approaches have been successfully used to develop composition–property models. However, these models are essentially black boxes in nature and suffer from the lack of interpretability. In this paper, we demonstrate the use of ML models to predict the composition-dependent variations of Vd and nd. Further, using Shapely additive explanations (SHAP), we interpret the ML models to identify the contribution of each of the input components toward target prediction. We observe that glass formers such as SiO2, B2O3, and P2O5 and intermediates such as TiO2, PbO, and Bi2O3 play a significant role in controlling the optical properties. Interestingly, components contributing toward increasing the nd are found to decrease the Vd and vice versa. Finally, we develop the Abbe diagram, using the ML models, allowing accelerated discovery of new glasses for optical properties beyond the experimental pareto front. Overall, employing explainable ML, we predict and interpret the compositional control on the optical properties of oxide glasses.  相似文献   

2.
The glass transition temperature (Tg) is a key parameter to investigate for application in nuclear waste immobilization in borosilicate glasses. Tg for several glasses containing iodine (I) has been measured in order to determine the I effect on Tg. Two series of glass composition (ISG and NH) containing up to 2.5 mol% I and synthesized under high pressure (0.5 to 1.5 GPa) have been investigated using differential scanning calorimetry (DSC). The I local environment in glasses has been determined using X-ray photoelectron spectroscopy and revealed that I is dissolved under its iodide form (I). Results show that Tg is decreased with the I addition in the glass in agreement with previous results. We also observed that this Tg decrease is a strong function of glass composition. For NH, 2.5 mol% I induces a decrease of 24°C in Tg, whereas for ISG, 1.2 mol% decreases the Tg by 64°C. We interpret this difference as the result of the I dissolution mechanism and its effect on the polymerization of the boron network. The I dissolution in ISG is accompanied by a depolymerization of the boron network, whereas it is the opposite in NH. Although ISG corresponds to a standardized glass, for the particular case of I immobilization it appears less adequate than NH considering that the decrease in Tg for NH is small in comparison to ISG.  相似文献   

3.
We present differential scanning calorimetry (DSC) analyses of seven French stained glasses from the 13th to 16th centuries. These glasses illustrate the dramatic compositional change from the antique soda‐rich glasses to potash‐ and lime‐rich compositions, resulting in drastic temperature and viscosity increases. We investigate the influence of chemical composition on glass thermal properties: glass‐transition (Tg), crystallization, and melting temperatures. We find that Tg varies from 533°C (soda type) to 638°C±17°C (potash type) to 685°C±5°C (lime type). The viscous slowdown of the melt as a function of the temperature, close to Tg, was modeled using the Vogel‐Tammann‐Fulcher equation. This enables temperature‐viscosity profile calculations, and suggests that recipes have been empirically optimized to reach similar thermoelastic properties suitable for glassmaking despite changing the nature of raw materials.  相似文献   

4.
Oxyfluoride glasses of xLaF3–(60 − x)LaO3/2–40NbO5/2 (x = 0, 5, 10, 35) and xLaF3–(60 − x)LaO3/2–30NbO5/2–10AlO3/2 (x = 0, 10, 20, 30) were prepared using a levitation technique. Both the glass-transition temperature, Tg, and onset crystallization temperature, Tc, were lowered by substituting a part of the oxygen with fluorine in the glasses. An appropriate amount of fluorine maximized the difference between the temperatures, ΔT (= Tc − Tg), indicating the improvement in the glass-forming ability. The atomic packing densities of the glasses were approximately 60%, which gradually increased with the fluorine content. The absorption edge of the glasses shifted toward the shorter wavelength region in the ultraviolet spectra and toward the longer region in the infrared spectra by fluorine substitution. In addition, in one of the oxyfluoride glasses, a wide transparency from 307 nm to 9.2 µm was realized. Furthermore, the glass exhibited superior optical properties, with a combination of a high refractive index, nd, of 2.020 and low wavelength dispersion, vd, of 30.1. The effect of fluorine substitution on the nd and its vd was analyzed using the Lorentz–Lorenz dispersion formula.  相似文献   

5.
《Ceramics International》2022,48(13):18094-18107
The impact of the cation field strength (CFS) of the glass network-modifier cations on the structure and properties of borosilicate glasses (BS) were examined for a large ensemble of mixed-cation (R/2)M(2)O–(R/2)Na2O–B2O3KSiO2 glasses with M+ ={Li+, Na+, K+, Rb+} and M2+ ={Mg2+, Ca2+, Sr2+, Ba2+} from four series of {K, R} combinations of K = n(SiO2)/n(B2O3) = {2.0, 4.0} and R =[n(M(2)O) ?+ ?n(Na2O)]/n(B2O3) = {0.75, 2.1}. Combined with results from La3+ bearing glasses enabled the probing of physical-property variations across a wide CFS range, encompassing the glass transition temperature (Tg), density, molar volume and compactness, as well as the hardness (H) and Young's modulus (E). We discuss the inferred composition–structure/CFS–property relationships. Each of Tg, H, and E revealed a non-linear dependence against the CFS and a strong Tg/H correlation, where each property is maximized for the largest alkaline-earth metal cations, i.e., Sr2+ and Ba2+, along with the high-CFS La3+ species. The 11B MAS NMR-derived fractional BO4 populations decreased linearly with the average Mz+/Na+ CFS within both K–0.75 glass branches, whereas the NBO-rich K–2.1 glasses manifested more complex trends. Comparisons with results from RM2O–B2O3KSiO2 glasses suggested no significant “mixed alkali effect”.  相似文献   

6.
7.
Differential scanning calorimetry (d.s.c.) and specific volume, V, measurements have been made on polystyrene glasses formed by cooling from the melt under pressure. Conventional glass temperatures, Tg(H) and Tg(V), defined by the points of intersection of enthalpy, H, or V curves for the glass and liquid agree well for one atmosphere glasses but show very different behaviour if the glass has been formed under pressure. This is due to the inability of the high pressure glasses to attain a suitable liquid conformation at atmospheric pressure. The thermodynamic state of densified glasses is discussed.  相似文献   

8.
It is shown that the glass transition temperature Tg of molecular (non-polymeric) glass formers correlates with molecular mass M as Tg(M) ∝ Mα, α = 0.51 ± 0.02. The subclasses of molecular glasses with homologous chemical structure but different M exhibit a similar universal correlation with significantly lower scatter. A possible explanation of Tg vs M correlation in molecular glasses is suggested. Comparing molecular glasses with polymers we found that in polymers Tg(M) dependence at small M (short chains) is similar to that in molecular glasses. At further increasing of the chain length the Tg(M) dependence in polymers begin to deviate from the universal Tg(M) correlation of molecular glasses and eventually saturates at some polymer specific Tg∞ value. We conclude that at least a substantial part of Tg(M) dependence of low-M polymers is common with molecular glasses mechanism that does not require chain-like structure. In particular, the model of Tg(M) dependence in polymers based on additional free volume on chain ends is not fully adequate at small M. Our picture provides an alternative explanation that in polymers a mechanism is in action which leads to a saturation of the normal Tg(M) dependence common with molecular glasses.  相似文献   

9.
《Ceramics International》2021,47(22):31666-31680
The present study replaced 3.30 and 9.00 mol.% BaO for CaO in a SiO2–B2O3–Al2O3–CaO–Na2O–P2O5 bioactive glass system used for implant coating applications. Variations of the glass structure, thermal properties, cytotoxicity, and radiopacity of glasses were studied. As demonstrated by the results, upon adding barium oxide to the glass structure, the weight density increased significantly, while a slight decrease in oxygen density was determined. Introducing barium oxide into glass composition did not cause any considerable change in the spectra of FTIR and Raman. It was demonstrated that the amount of bridging oxygen in the glass structure remained quite unaffected. The hot stage microscopy evaluations revealed further shrinkage of barium-containing frits due to lower viscosity and hence, higher viscous flow of these glasses. By substituting barium oxide for calcium oxide and increasing its concentration, the glass transition temperature (Tg) and the dilatometric softening temperature (Td) decreased, while the thermal expansion coefficient increased. Moreover, upon substituting 9 mol.% barium oxide for calcium oxide, a 30 °C reduction in maximum sintering temperature (Tms) of the glass was obtained, whereas the shrinkage rate was increased 1.7 times. It was indicated that the sintering process of barium-incorporated glasses would easily proceed without any phase crystallization. The barium-incorporated glasses exhibited more radiopacity. Additionally, no cytotoxic effect was caused by the substitution, and the Ba-containing glasses could be used for biomedical applications and implant coating as well.  相似文献   

10.
Crystallization, mechanical properties, and workability are all important for the commercialization and optimization of silicate glass compositions. However, the inter-relations of these properties as a function of glass composition have received little investigation. Soda-lime-silica glasses with Na2O-MgO-CaO-Al2O3-SiO2 compositions relevant to commercial glass manufacture were experimentally studied and multiple liquidus temperature and viscosity models were used to complement the experimental results. Liquidus temperatures of the fabricated glasses were measured by the temperature gradient technique, and Rietveld refinements were applied to X-Ray powder diffraction (XRD) data for devitrified glasses, enabling quantitative determination of the crystalline and amorphous fractions and the nature of the crystals. Structural properties were investigated by Raman spectroscopy. Acoustic echography, micro-Vicker's indentation, and single-edge-notched bend testing methods were used to measure Young's moduli, hardness, and fracture toughness, respectively. It is shown that it is possible to design lower-melting soda-lime-silica glass compositions without compromising their mechanical and crystallization properties. Unlike Young's modulus, brittleness is highly responsive to the composition in soda-lime-silica glasses, and notably low brittleness values can be obtained in glasses with compositions in the wollastonite primary phase field: an effect that is more pronounced in the silica primary phase field. The measured bulk crystal fractions of the glasses subjected to devitrification at the lowest possible industrial conditioning temperatures indicate that soda-lime-silica glass melts can be conditioned close to their liquidus temperatures within the compositional ranges of the primary phase fields of cristobalite, wollastonite, or their combinations.  相似文献   

11.
Glass components fabricated by the sintering route have wide-ranging applications. However, one issue is that the crystallization tendency of glass powders often leads to residual pore-glass interfaces and crystal-glass interfaces, thereby causing strong light scattering and rendering the sintered glass opaque. This issue is particularly pronounced in glasses with a low glass transition temperature (Tg) due to their weak bonding and thus high crystallization tendency. In the present study, a Bi2O3-ZnO-B2O3 glass with a low Tg of 364°C was fabricated using the conventional sintering method to explore whether transparent glass materials can be obtained. The temperature range of crystallization of the glass powders was analyzed using differential scanning calorimetry. X-ray diffraction was employed to analyze the crystalline phases formed in the sintered glasses. The microstructure of the sintered glasses was examined using scanning electron microscopy. The optical transmittance of the sintered glasses was measured using ultraviolet-visible spectroscopy. The results show that transparent sintered glasses with the highest transmittance of 54% at the wavelength of 650 nm can be obtained by using a coarser initial particle size, lower forming pressure, and an appropriate sintering temperature/time (430°C/30 min). It is suggested that this combination of processing parameters can suppress glass crystallization while maintaining a low glass viscosity during sintering.  相似文献   

12.
Mohit Gupta 《Polymer》2009,50(2):598-2946
The solid state structure and oxygen transport properties of biaxially oriented poly(propylene-graft-maleic anhydride) (PPgMA) reinforced with a low glass transition temperature (Tg) phosphate glass (Pglass) were investigated. Composites were prepared by melt blending PPgMA with up to 20 volume% Pglass. Melt blended composites were compression molded into monolayer structures and then biaxially stretched at a temperature above the Tg of the Pglass. Scanning electron microscopy confirmed that biaxial stretching transformed the spherical Pglass particles into platelets oriented in the plane of the film. Gas transport measurements revealed a reduction in the oxygen permeability by as much as 2 orders of magnitude compared to the unoriented PPgMA film. The permeability was analyzed according to performance models for dispersions of platelet-like fillers proposed by Cussler and Nielson. Aspect ratios ranging from 15 to 80 were obtained by fitting the experimental data to the models. Mechanical tests revealed that blending with Pglass increased the modulus of the stretched film but reduced the elongation at break only slightly.  相似文献   

13.
The structural relaxation of chalcogenide glasses is discussed within Tool–Narayanaswamy–Moynihan (TNM) formalism. The TNM parameters for more than 70 different glassy compositions are compared on the basis of the relaxation rate defined as RfT) = −(dTf/dlogt)i at the inflection point of the isothermal relaxation curve plotted on a logarithmic timescale. The RfT) depends on the TNM parameter ß and the parameter σ, combining the nonlinearity parameter x, the effective activation energy h* or the fragility m. It is shown that Rf(10) estimated at 10 K below Tg is useful for the prediction of structural relaxation kinetics in different amorphous materials. The chalcogenide glasses are, for example, compared with oxide glasses and organic polymers. For all these materials, the Rf(10) versus σ plot shows a well-defined pattern that is thoroughly discussed.  相似文献   

14.
Polystyrene was grafted with 1,4-dimethyl-2,5-dichloromethyl benzene in dichloroethane solution at 50°C using SnCl4 as a catalyst. Thermal analysis of grafted polystyrene samples using differential scanning calorimetry revealed two liquid-liquid transitions, Tll and Tll, in addition to the glass transition, Tg and the decomposition temperature, Td. The effect of the number of junctions per polystyrene chain on TgTll and Tll is examined and analysed.  相似文献   

15.
Viscosity and coefficient of thermal expansion (CTE) are both crucial properties in the design of new glasses for various applications. In this work, we extend the application of dilatometry to measure two important parameters governing the viscosity of glass-forming systems, viz., glass transition temperature and fragility index. We also describe a method to determine the dilatometric fictive temperature (Tf,DIL) and present data for five unique glass compositions covering a range of fragilities spanning 38-96, which are subjected to cooling and reheating rates in the range 1-30 K/min. The results show that the glass transition temperature obtained from the dilatometric method at 10 K/min (Tg,DIL) is consistent with both viscosity-based (Tg,vis) and DSC-based measurements (Tg,DSC). It is shown that the fragility of a liquid (mvis) can be determined by calibrating the dilatometric fragility (mDIL) with the same empirical model as in the calorimetric approach. Put together, we have developed a reliable method to measure the fragility and predict the viscosity curves of glass-forming liquids over a wide range (eg, 101-1016 Pa·s) without direct viscosity measurements, while simultaneously obtaining the CTE of the glass. However, this method is not suitable for glasses with a strong tendency toward phase separation or crystallization.  相似文献   

16.
We explored the structure and physical properties of Ge15Sb20Se65‐xSx (with x = 0, 16.25, 32.5, 48.75, and 65) glasses in order to screen the best compositions for the applications in photonics, since the laser damage thresholds in Se‐based glasses are too low although their optical nonlinearities are high. We found that, linear and nonlinear refractive index of the glasses decreased, but glass transition temperature Tg, optical bandgap Eg and the laser damage threshold increased with increasing S content. We further employed Raman scattering and high‐resolution X‐ray photoelectron spectra to probe the structure of the glasses. Through the analysis of the evolution of the different structural units in the glasses, it was concluded that, the heteropolar bonds (Ge–Se/S, Sb–Se/S) were dominated in these glasses. With the increase in chalcogen Se/S ratio, the number of the Se‐related chemical bonds (Ge–Se, Sb–Se and Se–Se) increased and that of S‐related chemical bond (Ge–S, Sb–S and S–S) decreased gradually, and Ge was prior to bond with S rather than Se. The elemental substitution thus had negligible effect on the glass structure. The change of the physical properties was mainly due to the difference of the strength of the chemical bonds between S–Ge(Sb) and Se–Ge(Sb).  相似文献   

17.
The mixed modifier effect (MME) is one of the most challenging puzzles in the field of oxide glasses, as there exists no universal quantitative theoretical model for accurately describing and predicting the nonlinear deviation of property values. In this paper, pairwise and ternary interactions are examined experimentally to understand the MME in a series of aluminosilicate glasses. By keeping the glass network former concentration constant and adjusting the molar ratios of three network modifiers (Na2O, K2O, and CaO), the MMEs in glass transition temperature (Tg), Vickers hardness (Hv), and activation energy (Ea) for aqueous dissolution for each modifier cation are investigated. We examine whether a pairwise interaction model is sufficient, or if ternary interactions also need to be included to predict the MME in these aluminosilicate glass systems. This work reveals that the pairwise model can be used to predict the MME for Tg in complex multiple-modifier glass systems using only two-body interaction factors. However, ternary mixed-modifier interactions are present in other properties such as Hv and Ea.  相似文献   

18.
With the advent of powerful computer simulation techniques, it is time to move from the widely used knowledge-guided empirical methods to approaches driven by data science, mainly machine learning algorithms. We investigated the predictive performance of three machine learning algorithms for six different glass properties. For such, we used an extensive dataset of about 150,000 oxide glasses, which was segmented into smaller datasets for each property investigated. Using the decision tree induction, k-nearest neighbors, and random forest algorithms, selected from a previous study of six algorithms, we induced predictive models for glass transition temperature, liquidus temperature, elastic modulus, thermal expansion coefficient, refractive index, and Abbe number. Moreover, each model was induced with default and tuned hyperparameter values. We demonstrate that, apart from the elastic modulus (which had the smallest training dataset), the induced predictive models for the other five properties yield a comparable uncertainty to the usual data spread. However, for glasses with extremely low or high values of these properties, the prediction uncertainty is significantly higher. Finally, as expected, glasses containing chemical elements that are poorly represented in the training set yielded higher prediction errors. The method developed here calls attention to the success and possible pitfalls of machine learning algorithms. The analysis of the SHAP values indicated the key elements that increase or decrease the value of the modeled properties. It also estimated the maximum possible increase or decrease. Insights gained by this analysis can help empirical compositional tuning and computer-aided inverse design of glass formulations.  相似文献   

19.
《Ceramics International》2022,48(15):21663-21670
In this study, two series of GaxSb40-xS60 (x = 4, 6, 8, 10 mol%) and GaySb36S64-y (y = 3, 5, 6 mol%) glasses were prepared and the relationship between their compositional and acousto-optic (AO) properties was investigated systematically for the first time. In the GaySb36S64-y system, the AO figure of merit (M2) increased as the Ga increased, and the maximum M2 of the Ga6Sb36S58 glass was 455.78 × 10?18 s3/g, which is ~301 times greater than that of fused silica and ~2.5 times greater than that of As2S3 chalcogenide (ChG) glass at 1550 nm. However, its thermo-optic coefficients (dn/dT) varied greatly (32.1 × 10?6 °C?1–57.2 × 10?6 °C?1), and acoustic attenuations (α) at 10 MHz were high, from 5.446 dB/cm to 7.274 dB/cm. In the GaxSb40-xS60 glass system, the M2 value and α at different ultrasonic frequencies gradually decreased with the improvement of Ga. Compared with the GaySb36S64-y system, the GaxSb40-xS60 glass system had lower α (at 10 MHz) and dn/dT, which are 5.001 dB/cm–5.563 dB/cm and 17.3 × 10?6 °C?1–55.6 × 10?6 °C?1, respectively. These results provide a significant reference for the further development of novel ChG glasses and help expand their application fields.  相似文献   

20.
《国际聚合物材料杂志》2012,61(12):1185-1189
ABSTRACT

In this article an attempt is undertaken to verify the approach already successfully applied to polymeric glasses for deriving a simple analytic relationship between the glass transition temperature, Tg , and Vickers microhardness, Hv , (for polymers it is Hv  = 1.57 Tg –571, Hv in MPa, Tg in K). On the basis of previously reported data for Hv and Tg of 12 inorganic glasses (lead-silicate-, alkali-silicate-, alumosilacate, and quartz glasses) a linear relationship in the form Hv  = 5.87 T g + 1740 (Hv in MPa, Tg in K) is derived. In addition, a critical analysis of the published attempt for theoretical deriving of the relationship between Hv and Tg is also offered.  相似文献   

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