LOW-FREQUENCY DIELECTRIC-DISPERSION OF L-THREONINE ADMIXTURED TRIGLYCINE SULFATE CRYSTALS (LTTGS)

For TGS crystals pure and admixtured with L-threonine, measurements of the permittivity epsilon and tg delta of the loss angle versus the me asuring field frequency (varied from 1 to 10(4) kHz) were performed in the temperature range from 80 to 330 K. For the first time the low-fr equency dielectric dispersion was observed in three temperature ranges : 180 to 210 K, 270 to 300 K and near the phase transition as the appe arance of additional maxima of epsilon and tg delta. The interpretatio n of these maxima is given in combination with radiospectroscopic resu lts. The dispersion in the three regions was interpreted as due to hin dered rotation of NH3 groups of GI glycines (180 to 210 K), hindered r otation of NH3 groups of GII and GIII glycines and domain structure (2 70 to 300 K) and partial repolarisation of domains (near T-C).