Luminescent solar concentrator samples using PMMA / SiO2 composites as the matrix with Erythrosine B are prepared. Three films of PMMA/ silica composition ration (70:30) %, (50:50) % and (30:70) % are prepared. The photostability of Erythrosine B doped PMMA/SiO2 composites is examined through four weeks exposure to sunlight. The obtained results show that the stability of collector increases with the increasing silica content. Moreover, the transition energy for electrons are direct allowed transition for all examined samples and the value of optical gap energy (Eg) increases with the increasing the silica content. However, the tail width of localized states in the band gap (Eu) decreases with the increasing exposure time due to the degradation of the dye. Emission spectra and quantum efficiency are also investigated. Erythrosine B is shown to have a higher fluorescence quantum yield in (30:70) % matrix. Collectively, these results suggest that PMMA/SiO2 composites provide the better system for use in fluorescent solar collector systems.