The electro-optical Kerr effect in binary mixtures of polar liquids

We report in this paper the measurement of the Kerr constant for six mixtures of polar liquids: acetone - quinoline, acetone - isopropyl benzene, acetone - nitromethane, acetone - water, acetone - acetic acid and water - t-butyl alcohol. The Kerr constant was measured at the wavelength of 632.8 nm using a pulsed electric field technique. A deviation from the pure additivity of the Kerr constant was observed for all the mixtures. This non-additive behaviour is discussed in terms of the refractive index, dielectric constant and molar volume of the components. We also include the fitting of our data to an equation for mixtures of polar liquids derived from a modified mean field theory, in which the interaction between the permanent dipole moments of the two liquids of the system is included. We also report for the first time the measurement of the constant B, at 632.8 nm, for four pure liquids: quinoline, t-butyl alcohol, isopropyl benzene and nitromethane, using the technique of short-pulse electric field.