Thesis (M.Sc.)--Chulalongkorn University, 1998

The reaction between p-ethylbenzaldehyde and benzoyl cyanide in an etheral solution and saturated with hydrogen chloride gas gave 4-chloro-2-(4'-ethylphenyl)-5-phenyloxazole in 68% yield. Its bromination by N-bromosuccinimide followed by dehydrobromination with potassium hydroxide in ethanol gave 4-chloro-2-(4'-vinylphenyl)-5-phenyloxazole as an effective scintillator. Poly [4-chloro-2-(4'-vinylphenyl)-5-phenyloxazole-co-styrene] with different mol ratios were synthesized using bulk polymerization at 70 ํC. AIBN was used as the initiator. The copolymer films and its various solutions in dichloromethane with various concentration have been characterized by absorption and fluorescence emission spectroscopy. It is found that the phenyl chromophores of polystyrene transfer excitation energy to the oxazole moiety in the region in which they strongly absorb. The excimer formation of the copolymer films has been monitored as a function of mol percent of diphenyloxazole content. The fluorescence quantum yields of the copolymer solutions in air and in degassed solution at the excitation wavelength of 260 nm were investigated.