Structural and optical properties of (100−x)Li2B4O7·x(Ba5Li2Ti2Nb8O30) glasses and glass nanocrystal composites

Abstract

Optically clear glasses of various compositions in the system (100-x)(Li₂B₄O₇)·x(Ba₅Li₂Ti₂Nb₈O₃₀) (5 ≤ x ≤ 20, in molar ratio) were fabricated by splat quenching technique. Controlled heat-treatment of the as-quenched glasses at 500 °C for 8 h yielded nanocrystallites embedded in the glass matrix. High Resolution Transmission Electron Microscopy (HRTEM) of these samples established the composition of the nano-crystallites to be that of Ba₅Li₂Ti₂Nb₈O₃₀. ¹¹B NMR studies revealed the transformation of BO₄ structural units into BO₃ units owing to the increase in TiO₆ and NbO₆ structural units as the composition of Ba₅Li₂Ti₂Nb₈O₃₀ increased in the glass. This, in turn, resulted in an increase in the density of the glasses. The influence of the nominal composition of the glasses and glass nanocrystal composites on optical band gap (E(opt)), Urbach energy (ΔE), refractive index (n), molar refraction (R(m)), optical polarizability (α(m)) and third order non-linear optical susceptibility (χ³) were studied.

Parasitic amorphous on single-domain crystal: Structural observations of silicate glass-ceramics

“…nanocrystallisation: a ≪ λ) or the closeness of the refractive index of the crystals to that of the matrix (refractive matching; M ~ 1) is chosen. Nanocrystallisation can be used to reliably prepare precursor glass which would be transparent in the visible wavelength even if there is a significant difference in the refractive index between the glass matrix and the crystallised nanoparticles; GCs consisted of multi-component glass and Nb-ferroelectrics is a typical example3031. On the other hand, the PSC-GC sample in this study is constructed by single-domain fresnoite in the matrix and parasitic nanoparticles (~10–20 nm), which correspond to the residual SiO 2 -rich amorphous phase.…”

Effect of CaO/MgO ratio on the optical and theoretical parameters of alumino‐borosilicate glasses

“…Also, the values for Urbach energy are higher in heat‐treated glasses varying from 0.62 eV to 0.86 eV. The defect concentration can be measured from the Urbach energy measurements . It could be observed that in heat‐treated glasses highest value for Urbach energy is for 17.5 CaMg glass which is also in the case of pristine glasses.…”

Effect of Bismuth on Physical and Spectroscopic Properties of ZnO-Li2B4O7-TbF3 Glasses

“…A large shift around 100 nm (violet to blue) is addressed to the increasing influence of NBO's. 30 To calculate the absorption coefficient, the following formula is used 31,32…”