Irgacure 651 is a photoinitiator to enhance the polymer degradation. It was found that the addition of the Irgacure 651 to PMMA accelerated|the photooxidative degradation, particularly at the early stages of exposure. The efficiency of formation of chromophoric groups in PMMA in the presence of the Irgacure initiator was significantly greater than in pure polymer. This suggests that the free-radical products of the initiator photolysis (mainly benzoyl radicals) are able to abstract hydrogen atoms from PMMA molecules.

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 24 months.
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.