A STUDY OF THE PHASE-TRANSFORMATION IN ANTHRANILIC ACID SINGLE-CRYSTALS

The electrical properties (resistance, dielectric constant and pyroelectric current) as a function of temperature in the range 30-degrees-C < T < 120-degrees-C of anthranilic acid single crystals (o-aminobenzoic acid, C6H4NH2COOH), were accurately measured and correlated to the structural phase change that has been observed at 81-degrees-C. The activation energies of the two phases were determined. The recorded DTA thermogram supports this phase change. In addition, the mean molar susceptibility chi-M of the powdered sample was accurately determined in the same temperature range; the result indicates that the structural phase change takes place at 81-degrees-C.