J. Phys. IV France
Volume 125, June 2005
Page(s) 781 - 783

J. Phys. IV France 125 (2005) 781-783

DOI: 10.1051/jp4:2005125180

Photoacoustic monitoring of Methylene blue irradiated

L.D. Lima1, F.R. Marciano1, M.S. Costa1, M.D. Silva2, P.R. Barja1 and D. Acosta-Avalos1

1  Instituto de Pesquisa & Desenvolvimento (IP & D), Universidade do Vale do Paraíba (UNIVAP), Av. Shishima Hifumi 2911, São José dos Campos 12244-000, SP, Brazil
2  Instituto de Pesquisas Espaciais (INPE), Av. dos Astronautas, São José dos Campos, SP, Brasil

The photoacoustic signal of methylene blue irradiated with red light (640 nm), by 1 minute, was monitored in time. It was observed that the PA signal increase with time, fact related with the diminution of the thermal effusivity of the methylene blue after irradiation. It was also observed that the signal undulates with periodicity of about 5 minutes. This behaviour is under study to better understand it.

© EDP Sciences 2005