Evaluation of quantum yields for decomposition of i-line sensitive photoacid generators

Quantum yields for decomposition of a series of i-line sensitive photoacid generators were evaluated in acetonitrile solution or in polystyrene films. Sulfonatc ester derivatives of N-hydroxynaphtaleneimide, fluorenone oxime, and Noxanthone oxime were investigated. Photolysis degree of photoacid generators was successfully estimated by UV or in situ FT-IR spectral changes. First-order decomposition profiles were observed for all photoacid generators on i-line irradiation. Quantum yields for decomposition (Phi(d)) were calculated based on the rate of decomposition and molar absorption coefficient of photoacid generators. The Phi(d) values were determined by using fluorenylideneimino p-toluenesulfonate as a standard. The Phi(d) values of photoacid generators derived from fluorenone oxime and thioxanthone oxime were similar to those of conventional photoacid generators. The relationship between thermal stability of photoacid generators and those Phi(d) values was also discussed.