In this work, the pure epoxy reinforced by TiO2 microparticles with weight percentage (2, 4, 6, and 8%) in particle size (50μm) by using molding method with shearing mixer at room temperature in order to prepare microcomposites for examined and measured their optical energy gap and optical constants of prepare specimens. The system used to measure Transmittance and Absorbance consisting laser semiconductor with wavelength (650nm), power (5mW) equipment with a power meter. The values of absorption coefficient less than 104 Cm-1 which indicated that the electronic transition in pure epoxy resin and epoxy /TiO2 microcomposites was indirect electronic transitions. The results showed that the energy gap of epoxy is 4.7eV and this value decreased within range of (4.7-2.05)eV when concentration of TiO2 microparticles increased from (2-8)wt.% respectively, Also the results showed that the optical constants which include the extinction coefficient (k), the refractive index (n), real part (εr) and imaginary part (εi ) of dielectric constant increased with increasing the weight fraction of TiO2 microparticles at wavelength 650nm.
