  The logarithmic slope of diffractive structure function is a potential
observable to separate the hard and soft contributions in diffraction, allowing
to disentangle the QCD dynamics. In this paper we extend our previous analyzes
and calculate the diffractive logarithmic slope for three current approaches in
the literature: (i) the Bartels-Wusthoff model, based on perturbative QCD, (ii)
the CKMT model, based on Regge theory and (iii) the Golec Biernat - Wusthoff
model which assumes that the saturation phenomena is present in the HERA
kinematic region. We analyze the transition region of small to large momentum
transfer and verify that future experimental results on the diffractive
logarithmic slope could discriminate between these approaches.
