In the present study, the casting method has been utilized for preparing different concentrations of Rhodamine B (Rh-B) doped in different transparent polymers. The spectral characteristics of the prepared samples are studied by absorption and fluorescence spectroscopy. The optical absorption measurements have been carried out in the wavelength region from 325 nm to 800 nm, and the fluorescence spectra has been investigated at different excitation wavelengths at room temperature. Besides, the effects of the concentration of the Rh-B dye and heat treatment temperature on the optical properties of the samples have been studied. Moreover, the effect of the thickness on the absorption and fluorescence has been included in the study. Based on the change of the absorption for Rh-B dye incorporation into different transparent polymer hosts, heat sensor testing has been investigated via recording the temperature changes in which the sample is alternately heated up to 70 °C and then cooled to room temperature in repeated cycles.