Refractive index and density changes in silica glass by halogen doping

The refractive index and density of halogen-doped silica glasses were measured as a function of fictive temperature, and the relationship between the refractive index and density was discussed on the basis of the Lorentz–Lorenz formula. The effect of halogen doping on the change in the refractive index was divided into two parts. The refractive index change was found to be strongly affected by structural rearrangement resulting from the termination of Si–O–Si bondings by halogens, as well as by the mean polarizability change caused by replacing oxygen with halogen.