EFFECT OF MODIFIER CONTENT ON THE CRYSTALLIZATION AND THE OPTICAL GAPS OF Tm3+ DOPED TeO
2-LiCl GLASS  


G. Özen

Faculty of Science and Letters; Department of Physics Istanbul Technical University
80626, Maslak-Istanbul, TURKEY


ABSTRACT


   
    Attention has been paid to tellurite glasses in recent years because they exhibit many useful and interesting physical properties that can be easily influenced by structural effects such as crystallization. In the present investigation, the effect of LiCl content on crystallization kinetics of (1-x)TeO2 – xLiCl glass and the optical band-gap and Urbach energies have been examined by differential thermal analysis (DTA) and ultraviolet-visible-near-infrared (UV/VIS/NIR) absorption measurements, respectively.

 

DTA scan curves of glasses taken at different heating rates were used to determine the Avrami constant which is a measure of crystallization mechanism. The activation energy values for the exothermic peaks were also determined graphically from the Kissinger-type plots using the analysis of Matusita and Sakka for the same glass compositions.

 

Absorption spectra measured between 350 – 900nm wavelength region were used to determine the optical band-gap and stimulated emission cross-sections for the 4f-4f transitions of  Tm3+ ions in these glasses as a function of glass composition.