Thermal and Mechanical Properties of Nd³⁺/Yb³⁺ Co-Doped Titanate Glass with Upconversion Emissions

Abstract

In the present work, Nd 3 + /Yb 3 + co-doped TiO2-La2O3-ZrO2 (TLZ) glasses which were previously prepared by the aerodynamic levitation method were characterized by thermal differential analysis (DTA) and micro-hardness tests. The DTA technique was used to study the thermal stability of the characteristic temperatures, the glass transition temperature (Tg), the crystallization onset temperature (Tc), and the crystallization peak temperature (Tp), of the rare earth doped titanate glasses. The thermal kinetic DTA-analysis of the Nd 3+ /Yb 3+ co-doped TLZ glasses was studied at heating rates of 5, 10, 15, 20 K•min-1. The activation energy (Ea) and the pre-exponential factor (A) were obtained by the Kissinger and Friedman methods. In addition, the Vickers hardness was higher than 7.50 GPa and fracture toughness was higher than 1.20 MPa• m 1/2 for all the investigated TLZ glasses by the micro-hardness test. Furthermore, the upconversion luminescence property was investigated at 808 nm laser excitation, and three intense upconversion emission bands were observed. The excellent upconversion fluorescence, good thermal stability, and high mechanical strength suggested that this class of materials has potential for practical application in frequency upconversion devices.