Irradiation spinodal

The samples for crosslinking kinetic studies were cast into thicker films (0.5 mm), sealed under high vacuum and gamma irradiated to 40 kGy. GPC (gel permeation chromatography) analyses of the irradiated samples suggested that chain scission for both PSD and PVME was minor. FTIR analyses indicated mutual grafting of PSD and PVME. The inverse of the spinodal temperatures obtained (Table 11.57) varies linearly with dose, and inversely with (number of monomers between crosslinks), as predicted by de Gennes... 

As an example, consider the study by Banerjee et al. (1984) on the effect of electron irradiation on the order-disorder transformation in (DIJ Ni4Mo. Electron micrographs and diffraction patterns were obtained during in situ electron irradiations at 50-1050 K in a HVEM. At temperatures below 200 K, the alloy completely disorders. At 200-450 K, only SRO was observed, and the transition between LRO and SRO, which occurs via the completely disordered state, is consistent with the concentration-wave description of the SRO structure and supports the concept of spinodal ordering. It is believed that an interstitial mechanism is responsible for maintaining the SRO. Above 450 K, LRO persisted for samples initially in this state and SRO was only preserved up to 550 K for samples initially in that state. Between 550 and 720 K, a mixed SRO-LRO state occurred, and at temperatures above 720 K a complete transition to SRO was obtained. It is believed that maintenance of LRO requires a vacancy mechanism. At temperatures below 800 K the SRO-LRO transition occurred in a continuous fashion, while above 800 K a nucleation and growth mechanism was operative. This behavior is characteristic of an ordering transition of the first kind below and above the coherent instability temperature. 

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