Structural and thermal stability criteria of Bi₂O₃–B₂O₃glasses

Abstract

Glasses with compositions xBi 2 O 3 -(100 − x)B 2 O 3 with 30 x 60 mol% have been prepared using the normal melt quenching technique. Infrared (IR) spectroscopy was used as a structural probe of the nearest-neighbor environment in the glass network. Assessment of the thermal stability of these glasses was achieved in terms of various simple quantitative methods based on the characteristic temperatures, such as the glass transition temperature, T g , the onset temperature of crystallization, T in , the temperature corresponding to the maximum crystallization rate, T p , and the melting temperature, T m . In this case, k gl may be more suitable for estimating the glass thermal stability in the above composition range. In this work the kinetic parameter K r (T ) is added to the stability criteria. The thermal stability of the glasses that were studied has been correlated with the activation energy of crystallization by this kinetic criterion and compared with those evaluated by other criteria. The results of both the criteria and the kinetic parameter K r (T ) confirm that the thermal stability decreases with increasing Bi 2 O 3 content. The former parameters, besides the average force constant of the BO 3 structural unit, were characterized and discussed in terms of the changes in the glass structure.

Effect of Bi2O3 on physical, optical and structural studies of ZnO–Bi2O3–B2O3 glasses

“…The shoulder around 840 cm À1 becomes more predominant as the Bi 2 O 3 content increases and is related to the symmetrical stretching vibration of the Bi-O bonds in the [BiO 3 ] groups [11]. The strong band at $700 cm À1 is due to the bending vibration of B-O-B linkages of BO 3 units [9,25]. The weak band observed at $520 cm À1 is due to m 4 vibrations of BO 4 tetrahedra and the weak bands below 500 cm À1 are due to Bi-O vibrations [10,11].…”

Ultrasonic investigations of some bismuth borate glasses doped with Al2O3

“…It is suggested that the addition of Bi 2 O 3 to borate networks results in the formation of Bi-O-Bi bonds, leading to a dramatic improvement in the chemical durability and thermal stability of the borate glasses. 9 On the other hand, the presence of the [AlO 4 ] 4− tetrahedra of Al 2 O 3 in borate-based glasses causes the boron to remain trico-ordinated and, consequently, to a certain extent, helps to maintain the constancy of the glass structure. In boroaluminate glasses containing alkaline-earth modifier ions, B 3+ and Al 3+ compete for tetrahedral sites, with most going to Al 3+ .…”

“…9 The glasses have loose-packed structure, are thermally unstable and have declining T g values. In the glasses studied, the values of T g decreased from 480 to 444 • C with the increase of Bi 2 O 3 content (table 1).…”

“…[4][5][6] Bismuth borate glasses have been extensively investigated due to their transparency in a wide spectral range from UV to IR, which makes them suitable for the fabrication of optical * Author for correspondence (ysaddeek@gmail.com) fibres, detection, sensing and laser technologies (laser host glasses). [7][8][9][10] On the other hand, the research in the field of glasses using ultrasonic parameters such as velocity and attenuation as a function of composition, besides the density and molar volume, has been carried out for many years. [11][12][13] In the study of glass samples, the ultrasonic wave propagation is greatly influenced by the density of the sample.…”

Dielectric Relaxation in CaO–Bi2O3–B2O3 Glasses

“…(1) is 159, for the present glasses (CBBO) reflecting the higher thermal stability than the other known Bi 2 O 3 -B 2 O 3 -based glasses. 15 The frequency (100 Hz-10 MHz) dependence of the dielectric constant (e 0 r ) and loss (D) at various temperatures (300-700 K) for the as-quenched samples is depicted in Figs. 2a and b, respectively.…”