The effect of barrier height on the photoabsorption process and refractive index changes are studied for the intraband transitions in spherical single electron Si quantum dots embedded in dielectric matrix. We use the effective mass approximation and consider (i) the finite, and (ii) infinite barrier height at the interface of the dot and matrix material. The results obtained for the dipole allowed S-P transition show that the increase in barrier height leads to blue shift in peak positions of absorption coefficient and refractive index change. We also investigate the effect of intensity and dot radius on the above parameters.