DYNAMIC GLASS-TRANSITION ABOVE THE COOPERATIVITY ONSET IN POLY(N-OCTYL METHACRYLATE)

Experimental heat capacity, dielectric, and shear spectroscopy data ar e reported on the alpha beta splitting region of poly(n-octyl methacry late). New facets of a major difference between the high-temperature a lpha relaxation at frequencies above the alpha beta splitting region a nd the ordinary alpha relaxation below are obtained: An alpha cooperat ivity onset in the splitting region and dominance of Rouse-Zimm-like m odes R for the alpha relaxation. The alpha and alpha relaxations are n ot related by temperature-time superposition.