In this article, temperature dependent refractive index of liquid crystals: 4-n alkyl benzoic acids ( nBA, where n = 6,8) are investigated towards the thermometry applications. Here the technique of image analysis in conjunction with Optical Polarizing Microscope is used to compute the refractive index of liquid crystals. This technique involves the computation of optical transmission, Absorption coefficient and reflectance from the liquid crystal textures. These parameters are determined from the intensities of the liquid crystal textures as a function of temperature. MATLAB software is used for the purpose of parameters computation from the textures of liquid crystals. The obtained results show that compound with n = 8 is more suitable for various thermometric applications than compound with n = 6 because it has been associated with strong variations in the refractive index values temperature.

Keywords : Refractive Index, Textures, Image Analysis, Transmission, Reflectance and Absorption Coefficient.