Polymer nanocomposites are formed by embedding polymer grafted nanoparticles in homopolymer host matrix. Polymers form glasses when cooled through their glass transition temperature (Tg) and the dynamics at the nanoscale around this temperature ultimately control properties that can be tuned for important applications (eg. viscosity and rheology). Fragility is a parameter which characterizes the rate of dynamics near Tg, and hence gives information of the glass forming ability of polymers. The addition of nanoparticles alters their glass forming abilities and gives control on final properties. In this proposal we plan to use polymer nanocomposite glasses made from grafted nanoparticles to study the effect of wettability of nanoparticle/polymer interface on the segmental dynamics.