The expression (70-x)B2O3-10ZnO-10CdO-10MgO-xBi2O3 Glasses containing B2O3, ZnO, CdO, MgO, and variable amounts of Bi2O3 were created using the melt quenching process. The observed rise in both density and molar volume of the glass samples as the Bi2O3 level increases suggests the formation of a more expanded structure with greater Bi2O3 content. There is a good degree of agreement between the observed values of band gap energy and Urbach energy estimated from the ASF model and Tauc model. The decrease in Eopt may be attributed to the increased concentration of non-bridging oxygen (NBO) inside the glass network, resulting in a disordered glass structure. The measured values of Λ and A indicate that the current glasses belong to group-II, namely typical ionic (basic) oxides. The non-linear optical properties of the current glasses, specifically n2, χ (1), and χ (3), showed an increase as the glass composition increased. The current glasses provide several benefits, such as a larger density. These glasses have a greater polarizability and an improved refractive index, making them highly sought-after materials for non-linear optical applications.

(70– x )B 2 O 3 -10ZnO-10CdO-10BaO- x Bi 2 O 3 glasses were prepared using melt quenching technique. The scanning electron micrograph of the studied glasses shows the surface without any existence of microstructures exhibiting a feature of amorphous phase. X-ray diffraction studies revealed amorphous nature of prepared glasses. The increment in both molar volume and density of glass samples as Bi 2 O 3 content increases indicates that a more opened structure is formed with higher content of Bi 2 O 3 . The T g value decreases as a function of Bi 2 O 3 content exhibiting increase in number of non-bridging oxygen atoms. The obtained values of band gap energy and Urbach energy from both Tauc model and ASF model are in good agreement with each other. The decrease in the E opt may also be due to the high concentration of NBO within the glass network. This causes a disordered glass structure arrangement which increases the excitation tendency of the electrons to the conduction band through the extension of the localized state in the gap. From the obtained values of α_O^2 - , Λ and A , the present glasses fall in the group (2) i.e., normal ionic (basic) oxides. It is concluded that all the prepared glasses have I c > 88

Machine learning techniques have been employed to predict the glass densities of xBi2O3–(70 − x)B2O3–20Li2O–5Sb2O3–5ZnO glasses using a data set of 2000 various B2O3 rich glasses using their chemical composition and ionic radius. The experimental density of present glasses strongly depends on Bi2O3 content which is increasing with bismuth content. The increasing density in bismuth doped glasses because the BO3 are converted into BO4 units, and besides BO3 units are less heavy than the BO4 units. The FTIR studies also confirm that the intensity of B–O–B bond decreasing with increasing Bi2O3 content which suggested that B–O–B bond in bond ring isolated to BO3 units transformed into BO4 units. In Raman Spectra the stretching vibrations of BO4 units shifting towards higher wavelengths with increasing Bi2O3 content. This shifting conforms that there is a structural changes in the glass-matrix and borate units converting from BO3 to BO4 units. The prepared glasses along with B2O3 rich glass data set train on various AI model such as gradient descent, Random Forest regression and Neural Networks to predict present density of glasses. Among the various models RF regression analysis model is successfully acceptable for the glass data with the highest R2 value 0.983 which end result conform that the predicted and experimental values correlated. ANNs stood the effective technique in prediction of glass density with the optimum performance resulting with Tanh as the activation function (R2 = 0.950). The minimum cost 0.018 obtained in the case of gradient decent function which also shows the better performance of regression model.

In the present study glass samples of (40 – x)Li20 · xNa2O · 10K2O · 50B2O3 and (40 ‒ x)Li2O · xK2O · 10Na2O · 50B2O3 (0 ≤ x ≤ 40 mol %) were prepared by melt quench technique. The cut-off wavelength varies non-linearly when Li2O is replaced with Na2O or K2O. The type of electronic transition in the present glass systems is indirect allowed. Using single oscillator model, the oscillator energy E0, the dispersion energy Ed, the static refractive index n0, the oscillator strength S0 and average oscillator wavelength λ0 were determined. The ratio of free carrier concentration to the free carrier effective mass Nc/m*, the optical relaxation time τ and ε∞ the high frequency dielectric constant were determined in the present glass systems. The real and imaginary parts of the optical conductivity dependence of energy in present glasses increases non-linearly with increasing photon energy.

Bi2O3-TeO2-B2O3-GeO2 quaternary glass system was prepared using a conventional melt quenching technique. The amorphous nature of prepared glasses was confirmed by X-ray diffraction measurement. The effect of Bi2O3 content on the B-O network structure was studied by FTIR spectroscopy. The existence of fundamental vibrations of germinates and tellurite network was confirmed by FTIR measurement. The study of optical absorption revealed that the indirect optical band gap (E-g) decreases with the increment of Bi2O3 content. Results of E-g shown that the E-g varied between 2.81 and 3.07 eV. The refractive index (n(o)) obtained using E-g was observed to change from 2.38 to 2.45. Besides, the molar refraction, oxide ion polarizability, optical basicity and interaction parameters were observed to vary with the increment of Bi2O3 mol% in the prepared glass samples. The glasses were observed highly ionic. In this study, mass attenuation coefficients (mu(m)), half-value layer (HVL), mean free path (MFP), effective atomic number (Z(eff)), radiation protection efficiency and exposure buildup factor (EBF) were determined experimentally and compared with Phy-X/PSD code. It was perceived that all prepared glasses have high mu(m) values at 356 keV and found between 0.231 and 0.257 cm(3)/g. The results of HVL and MFP indicated that prepared glass containing 65 mol% of Bi2O3 exhibited the lowest values of MFP (0.731 cm) and HVL (0.506 cm) at low energy. Obtained results of shielding parameters revealed that 65BiTBG glass has the highest gamma ray shielding capability than commercial shielding glasses and concretes.

MgO-Li2O-Bi2O3-B2O3 glasses were prepared by melt quench technique and analyzed with the help of refractive index, optical, IR, and Raman spectroscopy studies. The present glasses exhibited the mixed modifier effect (MME) through refractive index change non-linearly. The variation in the indirect optical band gap and band tailing in MgO content have been discussed with the glass structure. Based on the obtained values of αo2-, optical basicity, and interaction parameters, the present glasses were termed as very semi covalent acidic oxide glasses. Raman and Infrared spectra reveal that these glasses are built up of BO3, BO4 units of B2O3 and octahedral [BiO6], pyramidal [BiO3] units of Bi2O3 were observed.

Anew series of quaternary glasses with chemical composition xBi(2)O(3)-(80-x)TeO2-10B(2)O(3)-10GeO(2) where 40 <= x <= 65 have been prepared by melt quenching technique. X-ray diffraction measurements have been achieved to check the amorphous nature of the glasses. The effect of Bi2O3 content on the physical, thermal and optical properties of the prepared glasses was studied. It is observed that oxygen packing density decreased with the increase of molar volume with increasing Bi2O3 content implying the formation of non-bridging oxygen's and expands the glass. The glass transition temperature (T-g) increased whereas the glass stability decreased with Bi2O3. In addition to that, indirect optical band gap and Urbach energy values of the titled glasses have been calculated from Tauc plots using absorption spectra. The indirect optical band gap (E-opt) decreased with the increase of Bi2O3 concentration in the present glass system. The Raman spectroscopy at room temperature was employed to study the influence of bismuth oxide on the boron-oxygen network structure. The analysis of Raman spectra shows the presence of fundamental vibrations of TeO3, GeO6, BO3, BO4, BiO6 structural units.

New bismuth tellurite boro-germanate glasses according to composition xBi2O3-(80-x)TeO2-10B2O3-10GeO2 where (x=40, 45, 50, 55, 60 and 65 mol%) have been prepared by melt quench technique at 1150 ◦C. The room temperature optical absorption spectra have been recorded. The indirect band gap energy Eg was determined and found to decrease with Bi2O3 content. The increase in Urbach energy with glass composition indicates the decrease in structural stability. The ionic and covalent bonding parameters were determined. The present glasses are found to be 99 % ionic in nature. The two-photon absorption coefficient was found to increase from 11.89 to 14 cm/GW. The non-linear optical properties such as non-linear refractive index, linear optical susceptibility and third order non-linear optical susceptibility were evaluated using optical data. The authors determined theoretically the optical band gap (Eg) and refractive index (n) of the present glasses using optical electronegativity data. The relationship between Eg and n followed the relation Eg n4 = 99. The present glasses were found suitable for drawing optical fibers.

First time the mixed alkali effect (MAE) has been investigated in the glass system xNa(2)O-(30-x) Li2O-40B(2)O(3)-30GeO(2) (0 <= x <= 30 mol%) through density and optical absorption studies. The present glasses were prepared by melt quench technique. The density of the present glasses varies non-linearly exhibiting mixed alkali effect. Using the density data, the elastic moduli namely Young's modulus, bulk and shear modulus show strong linear dependence as a function of compositional parameter. From the absorption edge studies, the values of optical band gap energies for all transitions have been evaluated. It was established that the type of electronic transition in the present glass system is indirect allowed. The indirect optical band gap exhibit non-linear behavior with compositional parameter showing the mixed alkali effect.

The effect of fluorine substitution on the spectral properties of the xZnF(2)-(20-x)ZnO-40As(2)O(3)-40TeO(2) (x = 0, 4, 8, 12, 16 and 20 mol%) glass system was investigated by FTIR and Raman spectroscopies. The results demonstrate that TeO4 and TeO3 were among the primary structural units in the investigated glasses in addition to As2O3 pyramids and ZnO4 structural units. The addition of fluorine results in the reduction of Te-O-Te linkage due to a gradual transformation of trigonal bipyramidal TeO4 through TeO3+1 to trigonal pyramidal TeO3, which decreases the connectivity of the tellurite glass former network. The theoretical optical basicity of the studied glasses decreases with increasing ZnF2 content. (C) 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of Taibah University.

So far only a handful of publications have been concerned with the study of the mixed alkali effect in borate glasses and germanium glasses. In the present work, for the first time the mixed alkali effect (MAE) has been investigated in the glass system xNa(2)O (30 x)Li2O-40B(2)O(3)-30GeO(2) (0 <= x <= 30 mol%) through density, glass transition temperature and optical absorption studies. The density of the present glasses varies non-linearly exhibiting the mixed alkali effect. Using the density data, molar volume and oxygen packing density were evaluated. The glass transition temperature T-g was determined from the DSC measurements at a heating rate of 10 K/min. The strength of mixed alkali effect in T-g was found to be 27.9 degrees C. From the absorption edge studies, the values of indirect optical band gap have been evaluated. The indirect optical band gap exhibits non-linear behaviour with the compositional parameter exhibiting the mixed alkali effect.

Glasses of the xLiF-(50-x)Li2O-20SrO-30Bi2O3 system, with 0 ≤ x ≤ 20 mole % were studied by EPR and Optical measurements. The changes in both density and molar volume indicate structural modifications occur due to addition of LiF. The glass transition temperatures are observed to decrease with an increase in LiF content in the compositions. The local structure around Cu2+ ions has been examined by means of electron paramagnetic resonance and optical absorption measurements. It is observed that the spin-Hamiltonian parameters calculated from the EPR spectra are influenced by the glass composition. The Cu2+ ions are in well-defined axial sites but subjected to small distortion leading to the broadening of the spectra. The spin-Hamiltonian parameter values indicate that the ground state of Cu2+ is and the site symmetry around Cu2+ ions is tetragonally distorted octahedral. The optical absorption spectra exhibited a broad band corresponding to the d-d transition bands of Cu2+ ion. By correlating EPR and optical absorption data, the bond parameters are evaluated.

A glass system based on ZnF2-ZnO-As2O3-TeO2 was prepared. A number of properties such as glass transition temperature, glass stability, Elastic moduli, Debye temperature, poisons ratio studies. The results indicated that most of the properties are observed to be dependent on ZnF2 content.

Mixed alkali tungsten borate glasses xLi2O–(30–x) K2O–10WO3–60B2O3 (0 < x < 30) were prepared from the melts. These glasses were characterized using X-ray diffraction, differential scanning calorimetry and density measurements. Optical absorption studies were carried out as a function of alkali content to look for mixed alkali effect (MAE) on the spectral properties of these glasses. From the study of ultraviolet absorption edge, the optical band gap energies and Urbach energies were evaluated. The average electronic polarizability of the oxide ion, optical basicity and the interaction parameters were also evaluated for all the glasses. Many of these parameters vary non-linearly exhibiting a minima or maxima with increasing alkali concentration, indicating the mixed alkali effect. An attempt is made to interpret MAE in this glass system in terms of its glass structure.

In the present work, the compositional dependence of density, refractive index and glass transition temperature of xMgO-(25-x)Li2O-50B(2)O(3)-25Bi(2)O(3) glasses is studied. Impedance spectroscopy technique is employed on these samples and the data are analyzed using Cole-Cole type impedance response function. The AC conductivity behavior of the present glasses has been investigated in the frequency range from 100 Hz to 1 MHz and as a function of temperature the measured AC data are analyzed using the Jonscher's universal power law to explain the observed dispersive behavior of the electrical conductivity. The temperature and composition dependence scaling behavior in the AC conductivity are satisfactorily explained by scaling the AC conductivity sigma'(omega) by hopping frequency omega(p). The frequency response of dielectric constant epsilon' and dielectric loss tan delta as a function of temperature were studied. The tan delta peak shifts to higher frequency with increasing temperature, indicating dipolar relaxation character of dielectric loss in the present glasses. (C) 2012 Elsevier Ltd. All rights reserved.

The mixed-alkali effect (MAE) has been investigated in the glass system (40 − x)Li2O–xNa2O–10K2O–50B2O3 (0 mol% ≤ x ≤ 40 mol%) through density, modulated differential scanning calorimetry (DSC), and optical absorption studies. From the absorption studies, the values of the optical band gap (E opt) for direct transition and Urbach energy (ΔE) have been evaluated. The values of E opt and ΔE show nonlinear behavior with the compositional parameter. The density and glass-transition temperature of the present glasses also show nonlinear variation, supporting the existence of MAE. The infrared (IR) spectra of the glasses reveal the presence of three- and four-coordinated boron atoms. The specific vibrations of Li–O, Na–O, and K–O bonds were observed in the present IR study.

So far only a handful of publications have been concerned with the study of the mixed alkali effect in borate glasses containing three types of alkali ions. In the present work, the mixed alkali effect (MAE) has been investigated in the glass system (40–x) K2O–x Li2O –10Na2O–50B2O3. (0≤x≤40 mol%) through density and modulated DSC studies. The density and glass transition temperature of the present glasses varies non-linearly exhibiting mixed alkali effect. We report the mixed alkali effect in the present glasses through optical properties. From the absorption edge studies, the various values of optical band gap (Eo) and Urbach energy (ΔE) have been evaluated. The values of Eo and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. The band gap energy based average electronic polarizability of oxide ions αO2–(Eo) , optical basicity A(Eo) , and Yamashita–Kurosawa’s interaction parameter A(Eo) have been examined to check the correlations among them and bonding character. Based on good correlation among electronic polarizability of oxide ions, optical basicity and interaction parameter, the present K2O– Li2O–Na2O–B2O3 glasses are classified as normal ionic (basic) oxides.

Glasses with composition xLi(2)O-(30-x)Na2O-10WO(3)-60B(2)O(3) (where x = 0, 5, 10, 15, 20, 25, and 30 mol%) were prepared by the melt quenching technique. Density, refractive index and glass transition temperature varies non-linearly with glass composition indicting the presence of mixed alkali effect. Optical energy band gap for various indirect and direct (allowed and forbidden) transitions were determined using Tauc plots. IR spectral study reveals the existence of BO3 and BO4 groups with W-O-W vibrations in the present glasses. Based on good correlation among refractive index based electronic polarizability of oxide ions, optical basicity and the Yamashita-Kurosawa's interaction parameter, the present Li2O-Na2O-WO3-B2O3 glasses were classified as semi covalent oxides. (C) 2012 Elsevier B. V. All rights reserved.

Glasses in the system xZnF2–(20−x)ZnO–40As2O3–40TeO2 (x=0, 4, 8, 12, 16 and 20mol%) were prepared by normal melt quenching method. The change in density and ionic packing density in these glasses indicates the effect of ZnF2 on the glass structure. The optical constants of these glasses are determined over a spectral range, providing the complex dielectric constant to be calculated. The values of the optical band gap Eg for all types of electronic transitions and refractive index have been determined and discussed. The optical parameters such as N/m∗, ε∞, ωp, Ed and E0 have been estimated. The values of N/m∗ reflect an increase in the free carrier concentration with increasing ZnF2 content. This leads to an increase in the reflectance, R which in turn increases the refractive index.