We studied the influence of the optical excitation on three muonium centers Mu_T⁰, Mu_BC⁰, and Mu_BC⁺ in high resistivity silicon. These investigations were carried out on the spin precession signature of each center as a function of temperature. It is found that photoexcitation resulted in significant enhancements of the depolarization rates of the precession signals as the three muonium centers underwent interactions with photogenerated free carriers. The results are described by a three-state model involving transitions between Mu_T⁰, Mu_BC⁰, and Mu_BC⁺ as well as spin exchange processes.