Melting-solidification phenomena were studied in PEG (M = 10,000) and in (a) (1:1 w/w) PEG-dodecanoic and (b) (1:3 w/ w) PEG-octadecanoic acid mixtures (melted, mixed, solidified) by the MT and SingleScan Alternating (SSA) DSC techniques. With PEG, the reversible melting signal dominated, attributable to partial melting of lamellae which, nucleated by less-defected crystals melting at higher temps., were apt to recrystallize. No signal due to irreversible solidification was recorded. With the mixtures, type a produced signals due to reversible melting of the acid and PEG at 35-47 and 47-56degreesC, resp., and due to irreversible melting with max. at 44 and 52degreesC, resp., suggestive of minority of the well-developed PEG crystal structures. Solidification produced a clear reversible signal. Type b gave minor signals due to irreversible melting of PEG and of the acid (max 59 and 68degreesC, resp.). Solidification peaks did not overlap.