Processing and properties of novel ZnO–Bi2O3–B2O3 glass-ceramic nanocomposites

Abstract

Transparent optical glass-ceramics consisting of nanocrystals have the potential for use as optical devices such as waveguides, microlenses, and photonic crystals. ZnO–Bi2O3–B2O3 based glass ceramics were prepared via a melt quenching technique to assess parent glass and post-processed property evolution. Here, three large scale melts and six small test melts of the glass were melted at and around the 33.3 ZnO-33.3 Bi2O3- 33.3 B2O3 molar composition; some were also doped with small quantities of As2O3 for redox control or with LiNO3 as a nucleating agent. The physical and chemical properties including thermal behavior, transmission, elemental, and index of refraction of these melts were compared to assess their suitability as optical glasses and glass ceramics. Heat treatments were used to create transparent ZnO–Bi2O3–B2O3 glass ceramics containing BiB3O6 and Bi2ZnB2O7 nanocrystals. We correlate nucleation temperature, heat treatment temperature, and heat treatment duration with induced crystal phase formation. In addition to BiB3O6 and Bi2ZnB2O7 nanocrystals, ZnO was found to grow on the surface of some compositions. Compositional optimization and heat treatment procedures were developed to encourage volume crystallization while mitigating unwanted surface crystal growth. Laser-induced crystallization pads and lines were patterned in the glass to compare with and assess post-heat treatment phase and structure modification.