Visible light photoinitiating systems based on squaraine dye: kinetic, mechanistic and laser flash photolysis studies
New two-component photoinitiator systems for radical polymerization of acrylates are presented. The systems discussed comprise a synthetic dye 1,3-bis(p-bromophenylamino)squaraine and borate and onium salts as coinitiator. The effect of the composition of the system on the photopolymerization kinetics was analyzed. To this end, the photophysics and photochemistry of the dye under polymerization conditions were explored by means of stationary and time-resolved spectroscopic methods. The action mechanism of the different photoinitiators systems is discussed.