The work presented in the second of a series of three papers providing a comprehensive in-process study of polyolefin melt flows through the convergent section of slit dies. Here we focus on stress fields developed in several linear and branched polyolefin melts. Accurate measurement of stress optical coefficients derived from flow induced birefringence has enabled determination of shear and first normal stress difference fields in these polymers in an abrupt entry convergent flow geometry. The progression of stress growth with increase in melt flow rate is also described. The dimensionless stress ratio (centre line tensile stress to slit wall shear stress) has been identified as a quantity which correlates with the relative vortex size in the linear and branched polyolefins. Fully developed entry flows on melt passage into the slit section are also studied and reflect relaxation characteristics of each polymer.