Characterization of the physical properties of azo merocyanine dyes in different solvents and concentrations

The physical properties of five different samples of azo merocyanine dyes, each dissolved in three different polar solvents (Acetonitrile, Ethanol and 1-propanol) with three different concentrations (3 × 10−5, 2 × 10−5 and 1 × 10−5 mol/L) have been measured experimentally. The refractive indices of the samples have been determined with an accuracy of ±1 × 10−4 by using an Abbe Refractometer of measuring range from 1.300 to 1.700. The measurements have been performed at four different wavelengths (435.8, 546.1, 578.0 and 589.3 nm). Other parameters such as Cauchy's dispersion constants, resonance wavelength, molar polarizability, molar refractivity, absorption index and abbe number have been calculated. Also, viscosity, thermal expansivity and the effect of temperature on refractive index have been investigated. The intermolecular interactions between the solute and the solvent have been discussed. The physical characterization of merocyanine dyes provides valuable and important information needed for using them in many applications.