PHOTODEGRADATION OF POLY(ORTHO-(TRIMETHYLSILYL)-PHENYLACETYLENE) IN SOLUTIONS

Poly(o-(trimethylsilyl)phenylacetylene), poly(TMSPA) has been found to be highly stable in organic solvents in the absence of light and also in film form under ultra-violet/visible light irradiation. However, when poly(TMSPA) in chlorinated solvents is irradiated with ultra-violet and short-wavelength visible light, the polymer degrades and the rate of degradation is highest in the more highly chlorinated solvents such as CHCl3 and CCl4. After 2 h irradiation of a 2 x 10(-3) M CCl4 solution the molecular weight of poly(TMSPA) may decrease by almost two orders of magnitude. Ultra-violet/visible absorption spectroscopy suggests the presence of charge-transfer interaction between CHCl3 and CH2Cl2 with the poly(TMSPA) after irradiation. X-ray photoelectron spectroscopy results indicate that chlorine is incorporated into the polymer during the degradation process.