Abstract(s)
The rate of photomechanical formation of surface relief gratings (SRG) in thin films of azobenzene materials depends on their glass transition temperature (Tg), with an optimal Tg around 50–60 °C yielding the fastest SRG growth. Herein, the SRG growth of five analogous Disperse Red 1 molecular glasses with Tg values ranging from 9 to 71 °C was studied with two different laser wavelengths (488 and 532 nm). It was found that the optimal Tg for SRG growth increases with laser irradiance, from approximately 50 °C at 100 mW cm−2 to over 70 °C at 300 mW cm−2. Furthermore, the azobenzene glass with a sub-ambient Tg of 9 °C can inscribe self-erasable gratings that collapse spontaneously when irradiation is stopped in a repeatable fashion, thereby paving the way for light-controlled optical devices.