Photochromic gratings in sol-gel hybrid materials containing cyanoazobenzene chromophores

• Published in: Journal of sol-gel science and technology 2006, Vol.37 (1), p.57-62
• Main Authors: SERWADCZAK, M, KUCHARSKI, S
• Format: Article
• Language: English
• Subjects: Chemistry; Chromophores; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Diffraction efficiency; Ellipsometry; Exact sciences and technology; General and physical chemistry; Glass substrates; Gratings (spectra); Laser beams; Photochromism; Recording; Refractivity; Sol-gel processes; Spin coating; Tetraethyl orthosilicate; Thin films; White light
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-005-5156-x

The photochromic sol-gel hybrid materials containing cyanoazobenzene chromophores were described. These materials were obtained by copolycondensation of the functionalized triethoxysilane and tetraethoxysilane precursor. They were deposited on glass substrates via spin coating and casting techniques to provide thin transparent films. The UV-vis spectroscopy showed reversibility of the trans-cis photoisomerization of the chromophoric fragments. The reversible change of refractive index of the films on illumination with white light was determined by ellipsometry. The difference of real part of the refractive index of the sample was in the range 0.0053–0.0075. Formation of diffraction grating was achieved by two beam coupling arrangement using a 532 nm laser. The diffraction efficiency for the first order diffraction was in the range of 2–3.5%. The kinetics of photochromic grating recording and erasing was described by biexponential function approach.