Clear ring in discolored encapsulant

The signature is a band of transparent encapsulant around the edge of a cell or along a cell crack, surrounded by encapsulant that has turned yellow or brown. In glass/backsheet modules the browning sits in the middle of each cell and wide clear frames run along the cell edges. This is sometimes called a ring or doughnut pattern. Glass/glass modules usually discolour more evenly, but some cells can still show clearer areas. Clearer stripes or spots over a cell usually line up with cell cracks, so this pattern can make micro-cracks visible to the naked eye. The clear zones form because oxygen gets in through the breathable backsheet and bleaches the encapsulant near cell edges and cracks, which works against the yellowing. The pattern is found mainly by visual inspection. IV curve tracing and infrared thermography are secondary detection methods for the underlying discolouration.

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• sentence 4: support check: partial - Clearer stripes/points correlate with cracks and photobleaching makes micro-cracks visible by eye, but 'usually' is stronger than 'generally correlates' in glass/backsheet modules only, and the passages don't explicitly link the clear pattern as the means of visibility beyond photobleaching.
• sentence 5: support check: partial - Oxygen diffusion through the breathable backsheet and photobleaching counteracting yellowing near cell perimeters/cracks are stated, but the mechanism is described as preserving the UV absorber rather than directly bleaching the encapsulant, and the cell-edge versus crack location detail is only loosely tied. -->