ABSTRACT
For TTA doped polycarbonate, Schein (1992) has shown W to be field indepen dent over a wide range of fields. Young (1992) has further shown that W is approximately 0.20 and independent of thickness as well as field. Field indepen dent values of W have also been observed for DEH doped polycarbonate (Schein, 1992), DEASP doped polycarbonate (Schein, 1992), TPD doped polycarbonate (Yuh and Stolka, 1988), and a polysilylene (Abkowitz et al., 1990a). For DEH doped poly(styrene), Young (1992) has shown that W is independent of both field and thickness. For TPD doped polycarbonate, Yuh and Stolka (1988) have shown that W L~l/2 for constant fields. Kanemitsu and Einami (1990) studied an oxazole compound doped in a series of polymers. A key result was that W was strongly influenced by the polymer host. Polymers that have electron withdrawing groups give large values of W , while those with electron releasing groups give small W. Kryukov et al. (1990, 1990a) measured W for a series of polyarylenevinylenes doped into a polycarbonate and conclude that W can be signifi cantly reduced by the incorporation of a hetero donor group in the polymer side chains. Kanemitsu et al. (1991, 1992) have argued that W is dependent upon ct, increasing with increasing o\ In all cases, W decreases with increasing temper ature.
