Optical and positron annihilation spectroscopic studies on PMMA polymer doped by rhodamine B/chloranilic acid charge transfer complex: Special relevance to the effect of γ-ray irradiation.

Abstract Polymeric sheets of poly (methylmethaclyerate) (PMMA) containing charge transfer (CT) complex of rhodamine B/chloranilic acid (Rho B/CHA) were synthesized in methanol solvent at room temperature. The systematic analysis done on the Rho B and its CT complex in the form of powder or polymeric sheets confirmed their structure and thermal stability. The IR spectra interpreted the charge transfer mode of interaction between the CHA central positions and the terminal carboxylic group. The polymer sheets were irradiated with 70 kGy of γ radiation using 60 Co source to study the enhanced changes in the structure and optical parameters. The microstructure changes of the PMMA sheets caused by γ-ray irradiation were analyzed using positron annihilation lifetime (PAL) and positron annihilation Doppler broadening (PADB) techniques. The positron life time components (τ i ) and their corresponding intensities ( I i ) as well as PADB line–shape parameters (S and W) were found to be highly sensitive to the enhanced disorder occurred in the organic chains of the polymeric sheets due to γ-irradiation.