Viscoelastic fluid theories based on the left Cauchy-Green tensor history

After discussing the way the left Cauchy-Green tensor history can be used to formulate theories of viscoelastic fluids and showing that this class includes the simple fluids, some comments are made on three second-order fluid models regarding their stability in initial value problems. One second-order fluid model is due to Coleman and Noll, the second was proposed by the author and based on the left Cauchy-Green tensor, and the third is due to Harnoy. It is shown that all such second-order fluid models are inadequate because they cannot be stable in initial value problems and possess positive storage moduli as well.