3.2. Optical behaviour after curing: towards an unusually large level of reflected light intensity The cell is cured with UV light (with the wavelength of maximum intensity of 0.1 mW cm22 centred around 365 nm) at 112uC for 4 h, while the cholesteric helix is right-handed. When the reflectance properties are investigated at 112uC, the reflection wavelength is shifted from 4.2 to 3.8 mm (figure 4) as a result of polymer network formation in the LC matrix. The helical pitch of the blend is believed to decrease slightly in relation to the volume shrinkage resulting from the reaction of polymerization and crosslinking. Such a behaviour had previously been observed during the formation of three-dimensionally ordered polymer networks with a helical structure [15]. Figure 5 shows the transmission spectra of the same cell at 60uC, after cooling. At 60uC and before gelation, the selective reflection was close to 3.8 mm and associated with a left-handed helix. A chemical absorption band approaches close to 4.5 mm, as a result of which the normalized transmitted intensity diverges above 100%.