Stability factors were studied for polymer dispersed liquid crystal (PDLC) films which had been formed by ultraviolet (UV) initiated photopolymerization and liquid crystal phase separation. These stability studies emphasized long term exposures to high intensity light as a function of UV protection filters, and to high humidity (95% relative humidity (R.H.)) at an elevated temperature of 70°C. Various liquid crystal compositions were evaluated in PDLC films formed between conductive glass electrodes. The UWVIS exposure lifetime depended strongly on the wavelength cutoff of the protection filters. With coatings which had a 1% T cutoff at 394 nm, lifetimes greater than 2,200 h were obtained in a 1.1 kW Heraeus Suntest exposure system. Samples also showed greater than 1,000 h of stability, without degradation of properties, in the 95% R.H./70°C lifetime test.
[1]
G. Montgomery,et al.
A Light Control Film Composed of Liquid Crystal Droplets Dispersed in a UV-Curable Polymer
,
1987
.
[2]
Frederick G. Yamagishi,et al.
Morphological Control In Polymer-Dispersed Liquid Crystal Film Matrices
,
1989,
Photonics West - Lasers and Applications in Science and Engineering.
[3]
Shin-Tson Wu,et al.
Contrast Measurements For Polymer Dispersed Liquid Crystal Displays
,
1988,
Other Conferences.
[4]
Anna M. Lackner,et al.
Near Ultraviolet Photostability of Liquid Crystal Mixtures
,
1986
.
[5]
J. W. Doane,et al.
Field controlled light scattering from nematic microdroplets
,
1986
.