In a bowl combine the raisins, hot water, vinegar, cloves, nutmeg, and sugar and let stand.
In a large skillet heat the vegetable oil over moderately high heat. Season the pork chops with salt and pepper and cook until browned on both sides. Transfer browned chops to a shallow baking dish and place in a 300 degree F oven for 10 minutes or until cooked through.
In the drippings in the skillet, cook the onion, stirring occasionally, until tender. Add the raisin mixture, bring to a boil, and stir. Add the rhubarb, do not stir in rhubarb, cover and let simmer for 5 minutes. Stir the mixture and cook, uncovered, for another 3 minutes or until the rhubarb is just tender. Add any juices that have collected in the baking dish to the sauce. Adjust the seasoning with salt and pepper. Serve warm over pork chops.