Page 122 - Photoreactive Organic Thin Films

3. PHOTO-ORIENTATION BY PHOTOISOMERIZATION J Q J

absorption spectrum of pure cis by means of Equation 3A.12. So, e c is known
for any wavelength, and its value can be introduced in Equation 3A.6, which
allows the determination of <j> t' c and $ c' f. It is shown in the text that Fisher's
method is still valid for the determination of the cis absorption spectrum in
photo-oriented films when the irradiation light intensity is extrapolated to
infinity.