Ultra-slow Relaxation Dynamics in Triglycine Sulfate and D-Sorbitol Studied by Time-resolved Spectroscopy

The ultra-slow modes with a relaxation time much longer than 1 ns are discovered by a time-resolved spectroscopy in uniaxial ferroelectric (NH₂CH₂COOH)₃H₂SO₄ (TGS) and in glass-former HOCH₂(CHOH)₄CH₂OH (D-sorbitol). A mode discovered in TGS is a thermal relaxational mode and is proved to be the physical origin of the central peak found by Brillouin scattering. Two modes are discovered in D-sorbitol. One is a thermal relaxational mode. The other is a mode characterized by the Kohlraush-Williams-Watts function with a relaxation time _R. A remarkable result is that _R indicates a critical behavior not at the liquid-glass transition temperature T_g =–7°C but at the ergodic to nonergodic transition temperature T_c=33°C.This revised version was published online in November 2005 with corrections to the Cover Date.     

Proton spin-lattice relaxation time of triglycine sulfate (NH2CH2COOH)3 · H2SO4 near the transition point

The temperature dependence of the proton spin-lattice relaxation time T₁ of triglycine sulfate (NH₂CH₂COOH)₃ · H₂SO₄ is investigated near the transition point under several conditions. Any anomalous behavior of T₁ cannot be observed in contrast with an earlier report by Brosowski et al.