The nonlinear rheological behavior of entangled poly(ethylene oxide) (PEO) melts was studied by particle-tracking velocimetry (PTV) technique in a cone-plate geometry. In the absence of wall slip, the PEO melts exhibited internal macroscopic motions after shear cessation, when the imposed strain was larger than a critical value (between 1 and 1.5 strain units). This nonquiescent relaxation behavior of entangled melts has only recently been reported once in the literature involving a room temperature melt, and our work is the first PTV observation of nonquiescent relaxation at high temperature. (c) 2011 The Society of Rheology. [DOI: 10.1122/1.3596599]