Influence of water on molecular forms of rhodamine B in dip-coated thin films

Dip-coated thin films including rhodamine B have been prepared using the so l-gel reaction of tetraethyl orthosilicate under relative humidity of 30% a nd 60%. They have been aged under relative humidity of 20%, 60%, and 95% fo r 5 days. According to the absorption spectra, just after the preparation o f the films and under higher humidity, a larger amount of the dimers (H- an d J-types) were. formed in the films. Five days after the preparation of th e films and aged under higher humidity, the H-dimer increased. On the other hand, the J-dimer increased, regardless of humidity under which the films were aged.