Interaction energy in pairs of phthalazinium dibenzoylmethylid (PDBM)-protic solvent molecules estimated in the limits of the cell ternary solution model, by spectral means.

The dipolar compound Phthalazinium-dibenzoylmethylid (PDBM) was used as spectrally active molecule in order to analyze the molecular interactions in ternary solutions containing at least one protic solvent. In PDBM+protic solvent (1)+aprotic solvent (2) ternary solutions, PDBM can be involved both in universal and specific interactions reflected in solvatochromic effects. The protic solvent (or the solvent with the higher electric permittivity) was considered as being active from the interactions point of view.

Birefringence dispersion of N-(4-methoxybenzylidene)-4-butylaniline (MBBA) determined from channeled spectra.

The birefringence of MBBA, determined from the channeled spectra, decreases when the wavelength increases, showing a normal dispersion. The changes induced by an external electrostatic field acting perpendicular on the nematic director in the birefringence values were evidenced. The birefringence increases with the electrostatic field intensity which enhances the preferential alignment by the big values of the electric dipole moments induced parallel to the long MBBA molecule.