circuit stops responding after few seconds

[Abhinandan]

i have made a dark sensor circuit and it stops responding to light after a few seconds and the bulb that i am controlling remains always on.....i have uploaded the schematic and board layout pls help

 

[duke37]

Seems strange to me that you use Schottky diodes when almost any common diode would do. The 1N5819 is limited to 40V but you do not say what the input voltage is. You also do not say what transistors are used. I would think that a component is running too hard and is heating up, possibly T2.