<p>This research is aimed at investigating the potential of using fluorescent dyes, specifically fluorescein sodium salt dye (FSSD), embedded within epoxy resin (EP) as a material for luminescent solar concentrators (LSCs). LSCs are devices that capture and concentrate sunlight onto a smaller area, increasing the efficiency of solar cells. The study revealed a relationship between FSSD at different concentrations and EP molecules. The FSSD might be well-dispersed on a molecular level within the EP matrix. This homogeneous distribution is supported by the lack of distinct peaks in the XRD pattern, indicating the absence of any ordered crystal structure of FSSD within the composite. FSSD significantly influences the optical properties of the EP. It reduces light transmittance while increasing absorbance at specific wavelengths, which is crucial for efficient light capture in LSCs. The high polarizability of FSSD molecules and their random orientation can give rise to nonlinear optical phenomena. The enhanced light sensitivity of the FSSD@EP composite materials affects its nonlinear optical properties. These nonlinearities describe how the material’s response to light changes with increasing light intensity. The peak observed suggests a frequency range (10⁵–10⁷&#xa0;rad/s) where this energy dissipation is most prominent. This points towards a relaxation process occurring within the material at those frequencies. As the frequency of the electric field increases, both the real part (M′) and the imaginary part (M″) of the complex modulus (M*) are expected to change in the FSSD@EP composite materials.</p>