TiO2 - B2O3 composite thin films have been coated on microscope slides by a multiple dip-coating technique. Films produced with heating steps between the deposition of successive layers exhibit a better optical quality than those without. The former have a smaller grain size, less than 30nm as measured by SEM, and therefore result in less transmittance loss at the short wavelength region. X-ray diffraction studies show that these films are amorphous even after 500-degrees-C calcination, while films produced without intermediate heating become slightly crystallized after the same treatment. The thickness of the coated film is proportional to the number of layers applied. A film about 200nm in thickness can be produced by just four coatings. The refractive index of the film is 2.23 as evaluated from the transmission spectrum.
