The synthesis of sol-gel glasses containing organic and organometallic
molecular dopants has been well established as an approach for creating new
optical materials. Some of these properties are dependent upon chemical
reactions which occur in porous xerogel matrices during the sol-gel process
or when encapsulated molecules are exposed to other molecules in solution.
In this paper, the study of two different types of chemical reactions in the
pores of xerogel matrices is reported. In one case copper phthalocyanine is
used to characterize dimerization within the pores. The results show that
dimer formation is most likely to occur towards the end of the drying stage
as the dye concentration in the pores increases from solvent evaporation. A
second example involves the use of a pump-probe technique to determine the
rate of proton recombination inside the pores of silica monoliths. The
behavior of sols and gels is similar to aqueous solution while recombination
of protons in the xerogel seems to be affected by the walls of the
pores.