The dynamics of polymer chains in layered silicate/polystyrene nanocomposites was studied by anelastic spectroscopy. Two thermal activated peaks (

α

and

α

′peaks) appeared when the specimens were heated to a high temperature and they were related to glass transition and liquid-liquid transition

respectively. The activation energy was calculated based on Arrhenius equation and it showed that the activation energy of glass transition (

E

g

) is much higher than that of liquid-liquid transition (

E

ll

). Furthermore

the most interesting result for the activation energy was that there were two contrary trends for

E

g

and

E

ll

E

g

decreased and

E

ll

increased with the addition of clay platelets. The fragile parameter was analyzed and the variation of fragile parameters for the two transitions was also contrary to each other with the addition of clay platelets. All the results indicated that the confinement effect of clay platelets on the dynamics of polymer chain was scale dependent

and perhaps

the two transitions were produced by different mechanisms.