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Gamma irradiation-induced defects at doses of 0.5 and 5 MGy were studied in lithium sodium-borosilicate (LiNaBSi) and sodium barium-borosilicate (NaBaBSi) glasses, used for high-level radioactive waste immobilisation in the UK and India, respectively. X-band electron paramagnetic resonance (EPR), Raman and UV-Vis-nIR spectroscopies were used to characterise the glasses before and after irradiation. EPR and UV-Vis-nIR absorption spectroscopies revealed the formation of boron-oxygen hole centres (BOHC), electrons trapped at alkali cations or ET centres and peroxy-radicals (PORs) as defects common to both glasses. In addition, E− or polaron centres were observed in NaBaBSi glasses, possibly related to formation of elemental sodium colloids. Time-dependent thermal annealing at a range of temperatures, including those relevant to canister centreline cooling (CCC), which may be of relevance to geological disposal in future technical assessments, was carried out to study thermal stability of these radiation-induced defects. It was observed that PORs are the most thermally-stable defects in both glasses. The influence of glass composition on the segregation of sodium and the possible formation of metal colloids upon irradiation have been discussed.

Anthraquinones have been the subject of numerous photochemical studies and their photopolymerization activities have been examined under various conditions to improve more efficient photochemical systems. This article involves further detailed investigations into the photophysical, photochemistry and photopolymerisation properties of 4 commercial derivatives of 2-substituted anthraquinone, namely, 2-Bromomethylanthraquinone (2BA), 2 Chloromethylanthraquinone (2CA), 2 Ethylanthraquinone (2EA), 2 Hydroxymethylanthraquinone (2HA) and one novel synthesized anthraquinone, 2 Acryloxymethylanthraquinone (2AA). 2AA is synthesized from 2HA. The results from both spectroscopic and analysis studies proved the 2AA to having the ester link. Absorption spectroscopy and solvent shift data are used to characterise their spectral activity. Luminescence studies involving fluorescence and phosphorescence analysis indicates efficient intersystem crossing to triplet state and n-π* nature of the lowest excited triplet state. The polymerisation activity was studied using methyl methacrylate (MMA) and analysis of the cure rate was measured using the gravimetric method. All the compounds are shown to be highly dependent on the structure. However, the rate of polymerisation (Rp) was reduced in the presence of amine. This is consistent with other results, proving the behaviour of derivatives with n-π* configuration. Hardness tests for all compounds took place using a different formula of acrylated resin/monomer systems. The excited state characteristics of the methyl derivatives have also been examined using micro and nanosecond flash photolysis. Triplet absorption spectra of all the anthraquinone derivatives show a significant red shift in the region of 340–370 nm with increasing solvent polarity due to stabilisation of the lowest triplet state by solvent reorganization. Hydrogen atom abstraction takes place in 2 propanol, forming a semiquinone radical. In the presence of the tertiary amine, triethylamine, all anthraquinone derivatives show the formation of intermediary species related to either the exciplex or the radical ion pair. Under aerobic conditions, the first decay rate for all anthraquinone derivatives increases and showed oxygen to be a good quencher with a bimolecular rate constant of around 2 × 10 mol. dm s. Relative to benzophenone, the molar absorption coefficient, ε, and quantum yield of intersystem crossing, Φisc were calculated, and it is summarised that the value for Φisc for all compound is less than 1.00 and controls to a major extent their photochemical activities., The authors thank the University of Sains Malaysia for funding Hazira Mazah.

Raman spectroscopy and microscopy, along with all vibrational spectroscopic techniques, has proven itself to be a valuable analytical technique to quantitatively and qualitatively determine the molecular composition, properties of all kind of material systems. It has been successfully utilized in various fields of science, primarily due to the extraordinary versatility of sampling methods. The technique requires minimal sample preparation and can analyze samples of one monolayer thickness or of low sample concentration. Excellent spectral and spatial resolution and detailed fingerprinting can be derived from Raman spectra. Many technical issues such as fluorescence, poor sensitivity, or reproducibility have been overcome with the advances in instrumentation. Thus, its versatility of applications, rapidness of collection and easy analysis have made Raman spectroscopy an attractive analytical tool.