According to the optical transmission model of laser irradiated Polyethylene terephthalate (PET) fabric, the method of measuring the surface characteristic parameters, both the equivalent optical thickness and the gain of dye strength, is presented in detail. The PET fabrics untreated and irradiated by UV laser (308 nm, mJ/cm<sup>2</sup>, 10 pulses) are used in our experiment. They are dyed respectively by three disperse dyes (Ciba Terasil Red G 150%, Ciba Terasil Blue BG-02 200% and Ciba Terasil Navy GRL-C 200%) with various concentrations. The spectral reflectance distributions of the untreated and irradiated PET fabrics dyed are carried out with the color measuring and matching system (Datacolor, SF600plus). The experimental data indicated that the dye strength of disperse dye in the UV laser irradiated PET fabric was greater than that in the untreated, that the gain of dye strength is relative to dyestuff, and that the calculated reflectance of UV laser irradiated PET fabric is accordant well to the measured. The results show that the optical transmission model of laser irradiated PET fabric is reasonable and available.
UV-laser induced changes on surface structure and properties of Poly(ethylene terephthalate) (PET) fabric were discussed. Scanning electron microscope (SEM) observation revealed the morphological modification of PET fabrics with the ablation of 308nm excimer laser. The contact angle measurement and vertical drop test were used to find out the difference in the wetting property of the untreated and laser ablated PET fabric. Extra carboxylic radicals and increased amorphous part on the surface of the laser-ablated fabric were estimated by the attenuated total reflectance Fourier-transform infrared spectrum (ATR FT-IR) analysis. Dyeing property of the PET fabric was changed evidently by laser irradiation.