Effect of laser radiation on the structural and optical properties of Makrolon/Pocan polymer blend

Makrolon/Pocan is a polymer blend of polycarbonate that is amorphous in nature and is semicrystalline polybutylene terephthalate. Its trade name is Bayfol CR 4-2. It is used in a wide range of dosimetry. The authors believe that the current study is the first one that deals with the effect of laser irradiation on Bayfol CR 4-2. Samples of Bayfol films were treated with different laser fluences (3–30 J/cm2). The structural and optical characteristics of the Bayfol films were explored using x-ray diffraction and ultraviolet spectroscopy. The Urbach energy, refractive index, optical bandgap, optical dielectric constant, and dielectric loss were characterized and explained based on the laser fluence. The optical bandgap dropped from 3.04 to 2.65 eV for fluence of 30 J/cm2, associated with a rise in the Urbach energy. The authors attribute this to the increase of the amorphous phase inside the blend. Moreover, the color differences between the pristine and the irradiated films were calculated. The pristine Bayfol was uncolored. It exhibited noteworthy color changes during the laser treatment since the color difference attained a value larger than 5. This is well matching with the commercial reproduction on printing presses.