Two distinct Raman spectra have been reported for solid C-60 They diff
er in the exact position and relative intensities of the spectral line
s. Specifically, the frequency of the pentagonal pinch mode occurs at
1469 and 1459 cm(-1) in the two spectra. Several explanations have bee
n offered for the existence of a second spectrum, including the influe
nce of interstitial oxygen, a change in phase, the coexistence of sing
let C-60 with laser-pumped triplet C-60, and photopolymerization. We s
how that there are two Raman spectra for solid films of C-60 with vary
ing relative intensities according to the sample temperature even in t
he absence of oxygen. The reversibility of the two forms of C-60 With
temperature argues against photopolymerization. Finally pump-probe exp
eriments designed to detect either triplet absorption or singlet deple
tion indicate that neither of the two Raman spectra are due to triplet
C-60. We conclude that our previous explanation of C-60 is still the
most consistent with the observations.