UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2006 Meeting


Section: Optics, Spectroscopy, Plasma and Lasers


Title:
Optical and electronic changes induced by mixed valence metallic ions pairs in PVA doped polymers


Authors:
M. C. Valsangiacom(1), I.R. Andrei(2), G. A. Schinteie(1), M. Bulinski(3)


Affiliation:
1. National Institute for Materials of Physics, PO Box MG 7, 77125, Bucharest, Romania

2. The National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, Bucharest, Romania

3. University of Bucharest, Faculty of Physics 76900 Bucharest-Măgurele, P.O. Box MG-11


E-mail
cristina_v@infim.ro


Keywords:
nonlinear optics, metal doped polymers, light absorption, Mössbauer Spectroscopy


Abstract:
The electronic mechanisms induced by the UV exposure of the films realized from PVA doped with pairs of ions (iron, tin and antimony) was studied in relationship to their optical behavior by optical absorption, refractive index value and Mössbauer Spectroscopy. The main influence related to the evolution of the optical parameters in (Fe+Sn) and, respectively, (Fe+Sb) doped polyvinyl alcohol films, is related to charge transfer phenomena involving transition under the UV exposure. The complementary pair element contributes to the initial stabilization of the Fe3+ active species. The donor-acceptor mechanism implies two aspects: in the (Fe+Sn) doped PVA the electron is transferred from the tin species to the matrix, while in the (Fe+Sb) doped PVA the antimony species take electrons from the polymer matrix, showing a oxidizing mechanism in the first case and a reducing mechanism in the second case. The actual communication will emphasize the physical and chemical characteristics and their influence on materials properties.