  The optical properties of Nd$_{0.7}$Sr$_{0.3}$MnO$_3$ thin films have been
studied from 5 meV to 25 meV and from 0.25 eV to 3 eV, at temperatures from 15
K to 300 K and magnetic fields up to 8.9 T. A large transfer of spectral weight
from high energy to low energy occurs as the temperature is decreased below 180
K, where the dc resistivity peaks, or as the magnetic field is increased. The
optical data are found to be consistent with models that include both the
double exchange interaction and the dynamic Jahn-Teller effect on the Mn$^{3+}$
e$_g$ levels.
