Abstract
Absorption and electroabsorption measurements in the range of the charge-transfer absorption band were performed on amorphous films of TNF : PVK mixtures with different monomer ratio. Assuming localized excitation of the charge-transfer complex, the densities of charge-transfer complexes and of uncomplexed TNF and PVK monomers are determined from the optical data combined with the results of mass density measurements. The absorption and the electroabsorption response show a saturation above a ratio 0.6 : 1 of TNF : PVK resulting from a decreasing degree of complexing in these films with increasing portion of TNF. At a 1 : 1 monomer ratio of TNF : PVK only about 40% of the TNF molecules are complexed with PVK. This number rises with decreasing amount of TNF to about 72% in a 0.1 : 1 TNF : PVK film.