Structural and optical properties of pure PMMA and metal chloride-doped PMMA films

Films of PMMA and PMMA doped with CrCl3 or CoCl2 with different contents were prepared using the casting technique. The absorption spectral analysis showed that the Cr3+ are present in octahedral symmetrical form in the PMMA matrix, while Co2+ are present in mixed octahedral and tetrahedral form. The calculations of the ligand field parameters revealed the formation of metal-polymer complex. The dispersion studies of pure PMMA film and PMMA films doped with CrCl3 or CoCl2 were investigated using spectrophotometric measurements of transmittance and reflectance in the wavelength range 250-1500 nm. Analysis of the refractive index and absorption coefficient was discussed. The change of the calculated values of the optical energy gaps with increasing CrCl3 or CoCl2 content has been interpreted in terms of the structural modifications of the PMMA matrix. The Urbach tail in the mobility gap is discussed.