  The chemical evolution of the Galaxy is largely guided by the yields from
massive stars. Their evolution is heavily influenced by their internal mixing,
allowing the stars to live longer and yield a more massive helium core at the
end of their main-sequence evolution. Asteroseismology is a powerful tool for
studying stellar interiors by providing direct probes of the interior physics
of the oscillating stars. This work revisits the recently derived internal
mixing profiles of 26 slowly pulsating B stars observed by the Kepler space
telescope, in order to investigate how well the mixing profiles can in fact be
distinguished from one another as well as provide predictions for the expected
helium core masses obtained at the end of the main-sequence evolution. We find
that for five of these stars the mixing profile is derived unambiguously, while
the remaining stars have at least one other mixing profile which explains the
oscillations equally well. Convective penetration is preferred over exponential
diffusive overshoot for ~55% of the stars, while stratified mixing is preferred
in the envelope (~39%). We estimate the expected helium core masses obtained at
the end of the main-sequence evolution and find them to be highly influenced by
the estimated amount of mixing occurring in the envelopes of the stars.
