  In this paper we consider a modified fractional Maxwell model based on the
application of Hadamard-type fractional derivatives. The model is physically
motivated by the fact that we can take into account at the same time memory
effects and the time-dependence of the viscosity coefficient. We obtain an
ultra-slow relaxation response whose explicit analytic form is given by the
Mittag-Leffler function with a logarithmic argument. We show graphically the
main properties of this relaxation response, also with the asymptotic
behaviour.
