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We developed a new microspectroscopic system based on the ultrabroadband multiplex coherent anti-Stokes Raman scattering (CARS) process using a CCD camera with an InGaAs image intensifier. Owing to the gated amplification of the CARS signal by the InGaAs Image intensifier, the CARS signal was detected with less than 10 laser shots. As a proof-of-principle study, we applied our system to visualizing the heterogeneous structure of a blended polymer consisting of cellulose acetate and cellulose tris(phenylcarbamate). The clear vibrational contrast was observed under weak excitation conditions.

The penetration of water into a cellulose acetate (CA) film with m-terphenyl (m-TP) as a waterproofing agent (WPA) was investigated in real time by coherent anti-Stokes Raman scattering (CARS) microspectroscopy. Owing to the WPA, the water penetration was significantly suppressed. It was manifested by a small spectral change in comparison with the CA films without m-TP. Moreover, the amplitude of the Raman band at 1600 cm−1 due to the OH bending mode, which is the marker band of water penetration, was significantly smaller. The present results indicate that m-TP has significant effects as a WPA for CA films on the water penetration process.

The penetration process of water into a stretched cellulose acetate (CA) film was investigated in real time by coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The red shift of the C=O stretch mode due to hydrogen-bond formation was smaller than that of the unstretched film. The appearance of two Raman bands at 1605 and 1665 cm−1, which was instantaneously observed for the unstretched CA film, was reproduced but with much slower temporal response. The present results indicate significant effects of the stretching procedure on the water penetration process of CA films.