EFFECT OF ACCUMULATED RADIATION-DOSE ON PULSE-RADIOLYSIS CONDUCTIVITYTRANSIENTS IN A MESOMORPHIC OCTA-N-ALKOXY-SUBSTITUTED PHTHALOCYANINE

The transient conductivity induced by nanosecond pulse radiolysis of o cta-n-nonyloxyphthalocyanine has been studied as a function of accumul ated radiation dose, SIGMAD, from 10 Gy to 250 kGy. The end-of-pulse c onductivity, DELTAsigma(eop)/D, is unaffected by SIGMAD up to 150 kGy. Above this, DELTAsigma(eop)/D begins to decrease and at 250 kGy is 65 % of the low-dose value. An increase in the rate of decay of the trans ient conductivity in the solid state can be observed at values of SIGM AD as low as 10 kGy. On heating to the liquid crystalline phase and re solidifying, the conductivity decay returns to that found for the virg in material. However, DELTAsigma(eop)/D remains low. The solid to meso phase transition temperature, as monitored by differential scanning ca lorimetry, was found to be a few degrees lower after a total accumulat ed dose of 260 kGy.