AC calorimetric investigations of heat anomaly in frustoelectric liquid crystals

High-resolution ac calorimetric investigations have been made on liquid cry stals which exhibit a frustoelectric phase. In each case, a significant hea t anomaly which showed a non-Landau critical behavior was observed. The tra nsition was found to be weakly first-order. The data have been analyzed wit h a preasymptotic powerlaw equation which includes correction-to-scaling te rms, The critical amplitude has been discussed with the two-scale-factor un iversality.