LASER EVAPORATION OF SOME SOLID ORGANOSILICON POLYMERS

Continuous wave (cw) CO2 laser irradiation of some organosilicon polymers composed of -Me2Si-, -Me2SiMe2SiCH2-, RMeSi- and RMeSiMe2SiCH2CH2- units (where R = methyl, adamantyl, phenyl and hydrogen) leads to the evaporation of the polymer and is dominated by the formation of a solid deposit that has a continuous structure. It is assumed that chemical changes occur prior to the transfer of ejected material to the gas phase and that these consist mainly of the formation of high molecular biradicals or 1,2-disilacyclobutane monomer that both re-polymerize spontaneously upon their deposition onto a nearby cold surface. The mechanism of these specific decompositions of the polymers is assessed on the basis of the IR spectra of the deposits and, for the minor gaseous products, identification by GC MS techniques.