In the present work, the glass of composition 45GeO2–10 Na2CO3 ¬-10NaF–10ZnF2 – 25BaF2 (mol %) was prepared to investigate the crystallization behavior of BaF2 in the parent glass matrix. To accelerate the crystallization and to develop the up conversion fluorescence property ErF3 was doped in 0.5%, 1 % and 1.5 % (mol %). NH4F was added to compensate the fluorine loss. The glass composition was changed to 65GeO2–15 Na2CO3 – 5ZnO – 15BaF2 (mol %) due to excess of BaF2 phase in the original composition leading to high temperature of glass melting & crystallization of GeO2 before the crystallization of BaF2 . The casted glass was subjected to thermal treatment between 550 – 8000C at a heating rate of 1-20 C/min for different soaking time ranging from 1 hr to 5hr. To observe the effect of rare earth on crystallization, glass samples were examined under DSC to find the crystallization temperature. Phase authentication was carried out using X-Ray diffraction analysis
