We report on Raman and Fourier-transform infrared spectroscopy studies on lithium-implanted fullerene films containing endohedral Li@C-60. The measurements were performed as a function of temperature, polarization and time. They exhibit some significant differences compared to the pristine material: a broad band in the range 300-500 cm(-1) where the vibrational and rotational modes of endohedral Li were predicted, a strong broadening of the internal modes, a lineshift of the A(g)(1) and A(g)(2) modes and a change in the relative intensities and the depolarization ratios. A striking result is the temporal change in the spectra on the time scale of a few weeks.