  We present our results of pulse broadening time estimates and the study of
the frequency scaling of this quantity for 60 pulsars based on actual
multi-frequency scattering estimates. This research was based on our own
measurements, performed on the observational data and the profiles from various
pulsar profile databases, as well as the scatter time measurements that were
found in the literature. We were able to construct a database of over 60
pulsars with true multi-frequency $\alpha$ measurements, which allowed us to
revise the previously proposed relations between the scatter time spectral
slope and the dispersion measure (DM). We found that the deviations from
theoretical predictions of the value of $\alpha$ appear for pulsars regardless
of their DM, however the DM-averaged value of the scaling index is almost
constant except for pulsars with very high DMs. Based on the obtained slopes we
were also able to estimate the amount of scattering at the standard frequency
of 1 GHz. We found that while the estimated standardized pulse broadening time
increases with DM the relation seems to be much flatter than it was previously
proposed, which suggests higher values of the scatter time for mid-DM pulsars,
and lower values of expected pulse broadening for highly dispersed sources.
