The optical properties of polyEoxyisophthaloyloxy-(2-methoxy-p-phenylene)methylidene-(2-oxo-l,3- cyclohexanediylidene)methylidyne-(3-methoxy-p-phenylene)] (I) and poly[oxysebacoyloxy-(2-methoxyp- phenylene ) methylidene- ( 2-oxo- 1,3-cyclohexanediylidene ) methylidene- ( 3-methoxy-p-phenylene )-] (II) polymer films were studied. The transmission and absorption measurements were carried out in the energy range 1.9-3.2 eV at 300 K. The data on absorption coefficient versus photon energy were analysed and interpreted in terms of the Tauc model, (~h~o)~/2 = BX/2 (hto - Egpt). Analysis of experimental results shows that the absorption characteristics give a good fit to the Tauc model, and indicates that both polymers I and II have an indirect band gap. The values of the optical gap E~ pt and the slope of the Tauc plots B 1/2 were determined. The study shows that the indirect allowed optical transitions are the predominant transitions in the optical absorption process. From the data a correlation between optical band gap and polymer structure was observed and discussed.
Посилання на статтю:
Arylidene polymers: 15. Optical band gap and structural relationship of new polyester films of dibenzylidenecyclohexanone / M. A. Osman and A. Othman // Polymer. – 1992. – Vol 33. – P. 52-56.