ORIENTATION OF TOLUENE AND EFFECT OF THE PHOTOCHROMIC FULGIDE ETHYLIDENE](DICYCLOPROPYLMETHYLENE)-2,5-FURANDIONE AT THE AIR TOLUENE INTERFACE

The properties of the air/liquid interface of toluene have been examin ed using second harmonic generation of laser light. By selection of th e appropriate input laser polarization and output second harmonic pola rization, the molecular plane of toluene was found to be inclined by 4 2 degrees to the surface normal. The effect of the photochromic fulgid e (E)-[alpha-(2,5-dimethyl-3-furyl)ethylidene] (dicyclopropylmethylene )-2,5-furandione dissolved in toluene on the air/toluene interface was also studied. The presence of the fulgide was found to lower the inte nsity of second harmonic, and upon apparent monolayer formation, its m olecular plane was found to be inclined to the surface normal.