Influence of pressure on the photopolymerization rate of the linear orthorhombic polymer of C60

The photopolymerization of the orthorhombic C-60 polymer has been studied by Raman spectroscopy as a function of laser intensity at ambient and high pressure conditions. The Raman spectra at ambient pressure, excited by 514.5 nm, show irreversible changes at intensity similar to 3200 W/cm(2), while at high pressure the transformation rate increases and the required intensity drops to similar to 470 W/cm(2). Raman spectra recorded after pressure release, indicate that non-irradiated sample sites do not exhibit any changes. In addition, ambient pressure X-ray diffraction measurements on high-pressure treated, non-irradiated samples show no structural modification, revealing the dominant role of light in the polymerization processes. (c) 2006 Published by Elsevier B.V.