HfO2 thin films have gained much significance in recent years as a promising dielectric material for semiconductor electronics added to their wide applications in the field of optical filters as a high index material. The resistance of HfO2 films to impurity diffusion and intermixing at the interface as well as higher environmental stability have made these films one of the most extensively studied upon materials in laser optics, optical coatings and semiconductor domain. In the present study, Hafnium Oxide film was deposited on glass substrate using reactive oxygenated E-Beam deposition technique with in-situ quartz crystal thickness monitoring to control the film thickness and rate of evaporation. The coated substrate was optically characterized using spectrophotometer and Variable Angle Spectroscopic Ellipsometry (VASE) to determine its transmission spectra as well as optical constants. The coated sample was put under thermal stress testing in a test chamber with temperature variation from -40° to + 65° C in a cyclic manner for 7 cycles with a rate of temperature change of 5° C/minute. The coated sample was again optically characterized to investigate the effect of thermal cycling on its optical performance and physical parameters. Copyright © 2017 VBRI Press.