Thermal transitions of polysiloxane coatings onto glass fibers

It was estimated the relaxation temperatures of polymeric coatings on glass fibers. In order to do this, it was carried out the fluorescent response s tudy, as a function of temperature, of two dyes chemically bonded to the po lymeric coating. The glass fibers were treated with aqueous solutions of 3- aminopropyltriethoxisilane (APES) and a 50 % mixture of APES and 3-aminopro pylmethyldiethoxisilane (APDES). The fluorescent labels, pyrene-1-sulfonyl chloride (PSC) and 1-dimethylamino-5-naphtalenesulfonyl chloride (DNS), wer e attached to the silanized glass fibers by the formation of a stable and h ighly fluorescent sulfonamide conjugate (PSA and DNSA respectively). Emissi on spectra were recorded as a function of temperature in the range (133, 41 3)K. The results shown thermal transitions at low temperatures, which refle ct the high flexibility of the coupling region. In addition, that transitio n temperature clearly depends on the structure of the polymeric coating of the glass fibers.