In optically clear adhesive synthesis, free radical initiators can be photoinitators or thermal initiators. The amount of the free radical initiator is often in a range of 0.05 to 5 weight percent based on a total weight of monomers used. The following are some examples of initiators including both thermal and photo-initiators:
Thermal initiators
Azo type thermal initiators (Source). The grade number is the Celsius temperature at which the half-life in solution is 10 hours. Two more water soluble examples:
More Azo thermal initiators can be found from Wako-Chemical.
Above shows some common peroxides type thermal initiators. More peroxide thermal initiators from Arkema are:
photoinitiators
Benzoin or substitute benzoin type
Substituted acetophenones
More photo initiators can be found from Ciba special chemicals.