title: Experimental study of CdCl(2):CuCl photochromic coatings.
abstract: We present measurements of the spectral transmittance and photochromic response of CdCl(2):CuCl coatings. The coatings are also examined with the aid of electron micrographs. We explain the features observed in the spectral transmittance of darkened photochromic films, using a colloidal model obtained from the generalized Maxwell-Garnett theory. The colloidal model indicates the presence of ellipsoidal copper particles with a shape factor (minor axis/major axis) between 0.39 and 0.42 and mean ratios between 2.03 and 1.73 nm. The optical transmittance curve obtained in the faded state shows a peak near 280 nm attributed to Cu(+), and the curve in the darkened state shows two bands, a band located at 375 nm attributed to Cu(2+) and another at 600-610 nm assigned to colloidal copper particles.
authors.forename: H
authors.initials: H
authors.lastname: Marquez
authors.forename: J M
authors.initials: JM
authors.lastname: Rincon
authors.forename: L E
authors.initials: LE
authors.lastname: Celaya