Abstract
A poly (vinyl alcohol) PVA/Eriochrome Black-T (EBT) dye, and PVA/Eosin-Y (EY) dye composite film was prepared using a solution casting process. The dye-doped composite polymer films were characterized by UV-vis spectroscopy. An optical band gap (E
g
) of pure PVA reduced from 4.22 eV to 2.80 eV for PVA/EBT film and 2.14 eV for PVA/EY film respectively. This result indicates the occurrence of inter-molecular hydrogen bonding between the -OH functional group in PVA chains and sulfonate (EBT) and carboxyl group (EY) in dye molecules, respectively. Moreover, the experimental result of PVA/EBT and PVA/EY composite film showed the excellent properties of a large scale cut-off filter in the ultraviolet and visible range region.