  The polarization spectrum, or wavelength dependence of the polarization
fraction, of interstellar dust emission provides important insights into the
grain alignment mechanism of interstellar dust grains. We investigate the
far-infrared polarization spectrum of a realistic simulated high-mass star
forming cloud under various models of grain alignment and emission. We find
that neither a homogeneous grain alignment model nor a grain alignment model
that includes collisional dealignment is able to produce the falling spectrum
seen in observations. On the other hand, we find that a grain alignment model
with grain alignment efficiency dependent on local temperature is capable of
producing a falling spectrum that is in qualitative agreement with observations
of OMC-1. For the model most in agreement with OMC-1, we find no correlation
between temperature and the slope of the polarization spectrum. However, we do
find a positive correlation between column density and the slope of the
polarization spectrum. We suggest this latter correlation to be the result of
wavelength-dependent polarization by absorption.
