An on-line microcomputer based rotating light pipe reflectometer (RLPR) has been set up. Using this system we have investigated the optical properties of hydrogenated amorphous silicon semiconductor materials. The experimental results of reflectivity R(ω) has been analyzed by the Kramers-Kronig method. The complex dielectric function ε(ω) and the effective number of electron per single Si-atom have been calculated. The results show that Boron-doped hydrogenated amorphous silicon and thermal annealing improved the crystallinity.