  Prompt fission $\gamma$-rays are responsible for approximately 5\% of the
total energy released in fission, and therefore important to understand when
modelling nuclear reactors. In this work we present prompt $\gamma$-ray
emission characteristics in fission, for the first time as a function of the
nuclear excitation energy of the fissioning system. Emitted $\gamma$-ray
spectra were measured, and $\gamma$-ray multiplicities and average and total
$\gamma$ energies per fission were determined for the $^{233}$U(d,pf) reaction
for excitation energies between 4.8 and 10 MeV, and for the $^{239}$Pu(d,pf)
reaction between 4.5 and 9 MeV. The spectral characteristics show no
significant change as a function of excitation energy above the fission
barrier, despite the fact that an extra $\sim$5 MeV of energy is potentially
available in the excited fragments for $\gamma$-decay. The measured results are
compared to model calculations made for prompt $\gamma$-ray emission with the
fission model code GEF. Further comparison with previously obtained results
from thermal neutron induced fission is made to characterize possible
differences arising from using the surrogate (d,p) reaction.
