The evolution of an intrinsically acentric monolayer formed by self-assembly of a trimethoxysilane-functionalized, high-beta azobenzene-based chromophore from solution onto hydrophilic silicon oxide surfaces shows two distinctly different adsorption steps. The kinetics of the monolayer formation on sodium lime glass and polished silicon were monitored ex situ by a combination of aqueous contact angle measurements, optical spectroscopy, transmission second-harmonic generation (at lambda(0) = 1064 nm), and synchrotron X-ray reflectivity. The initial adsorption step from toluene onto the substrate surface at 80 degreesC is completed within minutes, k(1) approximate to 1 x 10(-2) s(-1), and results in an acentric material having similar to65% of the properties of a fully formed, dense monolayer (i.e., thickness, coverage, optical absorption, wettability, and nonlinear optical response). The second assembly stage is about 2 orders of magnitude slower, k(2) approximate to 1.3 x 10(-4) s(-1), and reaches completion after about 6 h.