We use the recently formulated hypothesis of semi-intercalation of an azo-dye Disperse Red 1 (DR1) into a biopolymeric material made of deoxyribonucleic acid (DNA) complexed with the cationic surfactant hexadecyltrimethyl-ammonium chloride (CTMA) to model the unique photochromic properties of the DR1:DNA-CTMA system. Kinetic Monte Carlo simulations accurately reproduce the main experimental results of laser dynamic inscription of diffraction gratings in this photochromic material: short response time, low diffraction efficiency, single-exponential kinetics and flat wavelength dependence. (C) 2009 Elsevier B. V. All rights reserved.