Characteristic relaxation times τ of the microscopic correlation in o-terphenyl and glycerol were obtained by a time-domain interferometry method using nuclear resonant scattering of synchrotron radiation. From the temperature dependence of τ, a new decoupling temperature 278 K, which is below the conventional decoupling temperature 290 K, was obtained for o-terphenyl. Furthermore, we found a liquid-like relation between τ and q (momentum transfer) as τ ∝ q-2 at 285 K in o-terphenyl and 260 and 265 K in glycerol. However, an anomalous q dependence of the slow β relaxation time, τ ∝ q-2.9 and q -3.8, was observed in deeply supercooled (265 K) and glass (240 K) states, respectively, in o-terphenyl, indicating specially restricted dynamics of the slow β process.
- Nuclear resonant scattering
- Slow dynamics
- Supercooled liquid
- Time-domain interferometry method