Chain length, polymer profile, and grating profiles

6 Chain length, polymer profile, and grating profiles 

A model [66, 68] describing the spatially inhomogeneous reaction kinetics of diacetylenes must take into account a kinetic chain length L, which depends on the polymer conversion P. The monomolecular reaction in a simple homogeneous situation then is given by 

For the experiments described so far, L can be assumed constant during the exposure time, because only very little conversion takes place. Furthermore, for all experiments de- 

Flere a polymer molecule grows parallel to the fringes contributing its whole chain length L to the polymer growth at point x, where it has been initiated. In the other case, a chain initiated in x contrihutes to the polymer growth in the whole interval [x - L 2, x +1/2]  

Integrating both Equations we see that in the second case the chain growth smears out the photoproduct distribution for a certain amount. This effect should be stronger if LI A approaches 1. For the quotient of both polymer modulations we get the ratio d. 

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