  Gamma-ray bursts (GRBs), which have been observed up to redshifts $z \approx
9.5$ can be good probes of the early universe and have the potential of testing
cosmological models. The analysis by Dainotti of GRB Swift afterglow
lightcurves with known redshifts and definite X-ray plateau shows an
anti-correlation between the \underline{rest frame} time when the plateau ends
(the plateau end time) and the calculated luminosity at that time (or
approximately an anti-correlation between plateau duration and luminosity). We
present here an update of this correlation with a larger data sample of 101
GRBs with good lightcurves. Since some of this correlation could result from
the redshift dependences of these intrinsic parameters, namely their
cosmological evolution we use the Efron-Petrosian method to estimate the
luminosity and time evolution and to correct for this effects to determine the
intrinsic nature of this correlation.
