Tellurite based glasses have been prepared with various glass compositions such as yBi(2)O(3)-xZnO-(100 - x - y) TeO2 glass system (y = 0.2, 1.0, 2.0, 3.0, 4.0, 5.0, and 8.0 mol% ratio and x = 14, 19, 19.8, and 20 mol%). The purpose of the work is to investigate the effect of glass compositions on the structure and hardness under the indentation loading test. Up till now, the experiences of the preparation of tellurite based glasses showed that it has high fragility structure at room temperature compared to boroxide, and chalcogenide-based glass materials. In this study, the thermal, mechanical and structural properties of Bi - based tellurite optical glass materials were investigated at room temperature. Results indicated that increased refractive index ratio of Bi has pronounce effect upon the transition temperature while the hardness value of the lassy material showed a reduction in response to this increased refractive index value of Bi. The obtained results further could be correlated with compositions that effects on the structural changes [for TeO4 (tbp) to TeO3 (tb)] having non-binding oxygen (NBO) due to the elastic deformation of Te-O bonding and expansion of interatomic distances when considered the data of the Vickers' hardness, FT-IR, and Raman spectra. Here, it can also be emphasized that obtained the thermal stability, (T = T-x T-g), of the glass material, decreases from 80 to 37 degrees C as the melting temperature increases from 800 to 1025 degrees C, possibly leading to a decrease in microhardness and deformation in the glass materials. (C) 2017 Elsevier B.V. All rights reserved.