ATTENUATED TOTAL-REFLECTION PROPERTIES AND STRUCTURES IN SPIROPYRAN LB THIN-FILMS

Attenuated total reflection (ATR) properties and structures were inves tigated for spiropyran (SP) Langmuir-Blodgett (LB) thin films. The SP LB films were deposited in the dark onto the cover glass evaporated wi th AE, The mixture of SP, arachidic acid (C20) and octadecane (HC18) w ere used for the LB depositions. The ATR properties changed with the m olar ratios of the mixtures, SP molecules were found to be better pack ed forming monolayers in the films with HC18 than without HC18. The AT R properties of the films with HC18 exhibited reversible changes cause d by the isomerization, but the charge was small because of the small rate of the isomerization of SP molecules. This result also indicates that the samples with HC18 were compactly packed. The ATR properties a lso changed with the temperature of heat treatment for the SP LB films with SP and photomerocyanine (PMC) forms. The changes of the structur es and the optical properties in the SP LB thin films could be evaluat ed from ATR measurements.