The Proposed Crystallization Behavior of the TeO2-Nb2O5-Bi2O3-Er2O3 Glass Ceramic System
The goal of this paper is to propose a method of determining the crystallization behavior of the TeO2- Nb2O5-Bi2O3-Er2O3 glass ceramic system. The polycrystalline form of this material created from the parent glass is of great interest for applications in fiber optics and laser systems, as it fluoresces in the short infrared wavelength range, and exhibits high optical gain. Understanding the crystallization kinetics of this material through a slowed nucleation and growth process will grant insight into the ideal process for optimizing the microstructure. Two separate parent glasses will be prepared, one containing 0.8 mol percent of the erbium dopant, and one containing 1.2 mol percent. The parent glasses would be produced by melting high purity powders at 850 °C, with crystallization subsequently occurring at 400 °C for intervals of 2 hours, ranging from 2 hour to 10 hour annealing times. Analysis would be conducted using scanning electron microscopy (SEM) for crystallite size determination, spectroscopy to determine transmittance in the short IR range, and X-ray diffraction (XRD) to determine crystal content and structure. It is predicted that crystal growth will follow a linear pattern as a function of time, with the dopant ions serving as nucleation sites, resulting in the two compositions having different percentages of crystallinity. This paper synthesizes prior research to support these predictions as well as detail the optical and structural properties of the proposed material.
Thesis completed in partial fulfillment of the requirements for the Alfred University Honors Program.
Honors thesis, Materials science, Ceramics, Glass